JPH11302041A - Production of wire for optical transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing a wire for optical transmission capable of keeping the curing a coating resin stably for a long period of time. SOLUTION: At the time of passing a wire 1 for optical transmission coated with a coating resin of a UV curing type together with an inert gas for cooling through a pipe 22 transmissible for UV rays and curing the coating resin by irradiating the pipe 22 with the UV rays outputted from a light source 21 for outside the pipe 22, the reflection intensity of the UV rays, which changes as the volatile component vaporized from the coating resin with the lapse of time by receiving the UV rays reflected on the surface of the pipe 22 adheres to the inside surface of the pipe 22, is measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method for manufacturing a wire for optical transmission, and more particularly, to a method capable of irradiating a coating resin with ultraviolet rays so as to continue to be cured stably for a long time.

[0002]

2. Description of the Related Art A method of passing a wire coated with an ultraviolet curable resin through a quartz tube and irradiating ultraviolet rays while flowing an inert gas through the quartz tube to cure the ultraviolet curable resin includes, for example,
JP-A-63-291669 and JP-A-8-291669
No. 152546 and the like.

FIG. 13 is a schematic view of an apparatus used for a conventional method of curing an ultraviolet curable resin. The wire 50 to be coated with the ultraviolet curable resin is applied with the ultraviolet curable resin through an applicator 52. The applicator 52 is supplied with an ultraviolet curable resin from a resin chamber 54 by a pump 56 to apply the resin to the wire 50. The wire 50 coated with the ultraviolet curing resin is applied to an ultraviolet irradiation device 58.
Supplied to The ultraviolet irradiation device 58 includes a quartz tube 60 through which the wire 50 passes, an ultraviolet irradiation light source 62, and a reflecting mirror 64 that reflects ultraviolet light. Further, the ultraviolet irradiation device 58
Is provided with means for supplying an inert gas such as nitrogen or argon to the quartz tube 60 from an inert gas supply source (not shown). Therefore, the ultraviolet curable resin applied to the wire 50 is cured by irradiating the ultraviolet light by the ultraviolet irradiating device 58.

According to this method, the inert gas is supplied to the quartz tube 6.
0 flows in the longitudinal direction together with the wire 50, so that turbulence does not occur and the surface of the coating resin can be hardened smoothly. In addition, since an inert gas flows only in the quartz tube, use of an inert gas is not required. The amount can be reduced and curing can be performed at low cost.

[0005]

However, if such a conventional method is continued for a long time, the volatile components from the coating resin applied to the inner surface of the quartz tube adhere to the surface of the quartz tube to reduce the amount of ultraviolet rays transmitted through the quartz tube. In some cases, however, the curing ability of the coating resin is reduced due to the irradiation of the predetermined ultraviolet rays, resulting in poor curing. Therefore, there is a problem that the production line must be stopped every time the production is performed for a certain period of time.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing an optical transmission wire capable of solving such a problem and stably curing a coating resin for a long time.

[0007]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method of manufacturing an optical transmission wire rod comprising a pipe for transmitting an ultraviolet ray together with an inert gas for cooling an optical transmission wire coated with a UV-curable coating resin. In a method for manufacturing a wire for light transmission, in which ultraviolet light output from a light source is irradiated with ultraviolet light from the outside of the pipe to cure the coating resin, the ultraviolet light reflected on the surface of the pipe is received, The reflection intensity of ultraviolet light, which changes because volatile components volatilized from the coating resin adhere to the inner surface of the pipe with the passage of time, is measured.

[0008] According to the method of manufacturing the optical transmission wire of the present invention, the volatile components volatilized from the coating resin adhere to the inner surface of the pipe with the passage of time, and the transmission efficiency of ultraviolet rays into the pipe is reduced. However, since the reflection of ultraviolet light from the surface of the pipe showing the same tendency is measured, it is possible to monitor a change in the intensity of ultraviolet light that penetrates into the pipe and substantially hardens the optical transmission wire. Therefore, it is possible to prevent the production line from being stopped unnecessarily and to prevent the occurrence of defective products due to insufficient curing.

In the method of manufacturing the optical transmission wire of the present invention, in the step of measuring the intensity of the ultraviolet light reflected from the pipe surface, there is a possibility that the ultraviolet light emitted from the light source may be directly incident on the light receiver. It is necessary to suppress ultraviolet rays other than the ultraviolet rays reflected from the pipe surface as much as possible.
For this purpose, it is preferable that the measurement be performed through a cylindrical measurement hole whose axial direction can be adjusted on a plane orthogonal to the longitudinal direction of the pipe while facing the pipe.

In the above-described measurement, it is preferable to intermittently measure by opening and closing a shutter provided in the measurement hole every desired time. Since the deposition rate of the volatile component requires a long time, intermittent measurement is sufficient. In addition, since the shutter is closed while measurement is not being performed, a rise in temperature of the light receiving portion is suppressed, measurement accuracy is improved, and deterioration of the light receiving portion can be prevented.

In the above method of manufacturing a wire for optical transmission, it is preferable to adjust and process the manufacturing conditions based on the measured ultraviolet light reflection intensity so that the coating resin has a predetermined degree of curing. The preferred method of adjusting and processing is to process volatile components attached to the inner surface of the pipe, adjust the production linear speed of the optical transmission wire, or control the output of the light source to transmit the light transmitted through the pipe. The purpose is to always supply ultraviolet rays having a desired intensity to the wire.

In the above-described method of controlling the output of the light source, it is preferable that the control is performed based on the measured reflection intensity of ultraviolet rays and the production linear speed of the optical transmission wire. In some cases, such as when a supply reel or a take-up reel is replaced, the linear velocity is changed during manufacture. When the linear speed changes, the irradiation time of the ultraviolet light changes, so that the output of the ultraviolet light source can be changed in accordance with the linear speed to keep the degree of curing constant.

[0013]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the description of the drawings, the same elements will be denoted by the same reference symbols, without redundant description.

In this embodiment, the coating resin is formed by applying the coating resin to a single optical fiber core wire having the coating resin applied to the outer periphery of the optical fiber or a plurality of optical fiber wires arranged in a plane. A method for irradiating an optical transmission wire such as an optical fiber tape core wire with ultraviolet rays to cure it stably for a long time will be described.

(Embodiment 1) In Embodiment 1, a case will be described in which the coating resin is cured by irradiating an optical fiber ribbon with ultraviolet rays. FIG. 1 is an overall configuration diagram showing an apparatus for manufacturing an optical fiber ribbon, and FIG. 2 is a plan view (a) and a front view (b) of an ultraviolet irradiation apparatus used in the manufacturing apparatus.

The apparatus for manufacturing an optical fiber ribbon shown in FIG. 1 comprises a plurality of supply reels 10 for feeding out an optical fiber 2, a plurality of optical fibers pulled out via a supply tension control dancer roller 11 and a guide roller 12. A grooved guide roller 13 for arranging the wires 2 in a plane, a coating device 14 for introducing the uncured UV-curable resin from a pressurized supply tank 15 and applying it collectively in a tape form, and an inert gas supply tank 17 UV irradiator 16 for irradiating and curing ultraviolet light on optical fiber ribbon 1 while supplying cooling gas from hard disk, and hardened optical fiber ribbon 1
And a take-up reel 20 for taking up the paper through a take-up tension controlling dancer roller 19 at a predetermined speed.

As shown in FIG. 2, the ultraviolet irradiation device 16
It has a pipe 22 through which the optical fiber tape core wire 1 passes together with an inert gas and has good transmission of ultraviolet rays, a light source 21 disposed outside the pipe 22, and an elliptical reflecting mirror 23 having two focal points. Each of the mirrors 23 has a light source 2
1 and a pipe 22 are arranged and housed in a housing 24.

Further, holes 25a and 25b are formed in the reflecting mirror 23 and the housing 24, respectively, and a cylindrical measuring hole 25 for introducing ultraviolet rays is formed, and the outer wall of the housing having the hole 25b is opened and closed. Shutter 26 for transmitting and blocking ultraviolet rays
A light receiving element 27 is provided outside the shutter 26, and the light receiving surface of the light receiving element 27 is fixed at a predetermined angle with respect to the axial direction of the measurement hole 25. The measurement hole 25 may be formed by only the holes 25a and 25b, and may be formed by the holes 25a and 25b.
Alternatively, a cylindrical body may be provided between b. Such a measurement hole 25 faces the pipe 22 and is formed so that the axial direction can be adjusted on a plane orthogonal to the longitudinal direction of the pipe 22.

FIG. 3 is a plan view of an ultraviolet irradiation apparatus having another configuration used in this manufacturing apparatus. The configuration of the reflector is 2
One focus f _a, elliptical reflector 23a and two focus f _b with f _c, in the elliptical reflector 23b with f _c, 3 single focus f _a a f _c as common focus, f _b, the f _c formed having, f _a, respectively f _b sources 21a, 21b are arranged, the focus f _c are arranged pipes 22. In this configuration, since the two light sources irradiate the optical fiber ribbon 1 passing through the pipe 22, the irradiation capacity is doubled.

Next, the configuration of each member will be described. The optical fiber 2 sent out from the supply reel 10
The resin is coated on the outer periphery of an optical fiber made of quartz glass. The resin may be colored differently to distinguish it from other optical fiber strands. FIG. 4 is a perspective view showing a configuration example of the optical fiber ribbon. The optical fiber ribbon 1 is formed by coating and curing the outer circumference of a plurality of optical fiber strands 2 arranged in a plane with a coating resin 3. It is formed. As the coating resin 3, a urethane acrylate-based ultraviolet curable resin or a silicone resin is used.

As the light source 21, a cylindrical metal halide lamp which outputs ultraviolet rays substantially uniformly in the passing direction of the optical fiber ribbon 1 is used. The pipe 22 is made of quartz glass or the like that easily transmits ultraviolet light. FIG. 5 is a side view showing a state in which the optical fiber ribbon and the inert gas pass through the pipe. The inert gas such as He, Ar, or N ₂ is supplied to the pipe 2 provided at the upper end of the pipe 22.
8 and discharged through a pipe 29 at the lower end.

Next, a method of curing the coating resin using the above-described ultraviolet irradiation device 16 will be described. Optical fiber ribbon 1 coated with UV-curable coating resin 3
Is introduced from the upper end of the pipe 22, as shown in FIG. Ultraviolet light output from the light source 21 during this time passes through the pipe 22 to cure the coating resin 3. At this time, if the inside of the pipe 22 is filled with oxygen in the air, the curing action of the coating resin 3 is impaired, so that the air is replaced with an inert gas to promote the radical reaction. Further, the inert gas has an effect of suppressing a rise in temperature in the pipe 22.

On the other hand, the optical fiber ribbon 1 is a pipe 2
While passing through the inside 2, volatile components volatilized from the coating resin 3 adhere to the inner surface of the pipe 22. Therefore, as the amount of volatile components adheres with the passage of time, the transmission of ultraviolet rays is hindered, and the intensity of ultraviolet rays reaching the optical fiber ribbon 1 is reduced, and the uncured coating resin 3 appears.

FIG. 6 is a diagram showing a path on which the ultraviolet light emitted from the light source 21 is reflected on the surface of the pipe 22. Ultraviolet rays are reflected on the outer surface and the inner surface of the pipe 22 due to a difference in refractive index between the air and the pipe. Among the ultraviolet rays U _i incident on the pipe 22, the reflected light U _ra reflected on the outer surface is constant irrespective of the attachment of the volatile component 4 to the inner surface, but the reflected light _Urb from the inner surface is not reflected on the inner surface. If the volatile component 4 adheres to the surface, absorption and scattering occur, so that the content decreases. Further, the volatile component 4 attached to the inner surface reduces the intensity of the reflected ultraviolet light, decreases the intensity of the ultraviolet light penetrating into the pipe 22, and weakens the curing of the coating resin 3. Therefore, the cured state of the coating resin 3 can be estimated by measuring the intensity of the ultraviolet light _Urb reflected from the surface of the pipe 22 that changes over time.

Next, a method for measuring the ultraviolet light reflected from the surface of the pipe 22 will be described. FIG. 7 is a plan view of an ultraviolet irradiation device showing a method of measuring ultraviolet light reflected from the pipe surface. Part of the ultraviolet light U emitted from the light source 21
_i can reach the measurement point directly. On the other hand, some other ultraviolet rays _Ur can reflect the surface of the pipe 22 and reach the same measurement point. Here, the ultraviolet rays U _i are unnecessary light and need to be reduced. for that reason,
This can be achieved by providing holes 25a and 25b in the reflecting mirror 23 and the housing 24 to form the cylindrical measurement hole 25, and adjusting the position and the axial direction of the tube.
The closer the axial direction and the incident direction of the ultraviolet light U _r become parallel, the more reflected light U _r can be input to the light receiving element 27. The closer the axial direction and the incident direction of the ultraviolet light U _i become, the more direct light becomes. U _i can be reduced.

In the above-described measurement, since the deposition of the volatile component requires a long time, accurate control can be performed even if the shutter 26 is opened and closed at desired times and measured intermittently. Since the shutter 26 is closed during the non-measurement period, the temperature rise of the light receiving element 27 is suppressed, and the measurement accuracy is improved.

Next, an example of manufacturing an optical fiber ribbon consisting of four optical fibers using the manufacturing apparatus shown in FIG. 1 and the ultraviolet irradiation apparatus shown in FIG. 2 will be described. FIG. 8 is a graph showing a change in the relative value of the ultraviolet irradiation intensity and the change in the relative curing degree of the coating resin when the optical fiber ribbon is continuously manufactured while keeping the output of the light source constant. In the figure, the ultraviolet irradiation intensity (marked with a circle) is a relative value of a value obtained by measuring the reflection intensity of the ultraviolet light from the pipe 22 at intervals of 30 minutes.
The marks ● are relative values obtained by measuring the intensity of ultraviolet light that enters the pipe 22 before and after the end of the production. Also, ×
The marks are relative values obtained by measuring the degree of curing of the resin of the manufactured optical fiber ribbon 1 at regular intervals in the length direction. FIG.
The relative irradiation intensity and relative curing degree of the ultraviolet light shown in (1) indicate the number of cores of the optical fiber 2 forming the optical fiber ribbon 1, the type of the coating resin 3, the production speed, or the inertness introduced into the pipe 22. The tendency changes depending on conditions such as the type and flow rate of gas.

According to this result, when about 6 hours have passed since the start of the production, the intensity of the ultraviolet irradiation tended to decrease due to the volatile components of the coating resin 3 attached to the inner surface of the pipe 22, and 1
After 0 hour, it decreased to about 85%. On the other hand, it was confirmed that the relative degree of curing of the manufactured optical fiber tape core wire 1 was reduced in accordance with the irradiation intensity of the ultraviolet rays. That is, the intensity of the ultraviolet rays that enter the pipe 22 due to the volatile components adhering to the inner surface of the pipe 22 and the intensity of the ultraviolet rays
It can be seen that the intensity of ultraviolet light reflected from the surface of No. 2 shows the same tendency.

Therefore, by measuring the change in the intensity of ultraviolet light reflected from the surface of the pipe 22, the cured state of the coating resin can be detected, and countermeasures can be taken. First
The method of (1) is to stop the production once when the intensity of the reflected ultraviolet light falls to a predetermined value, and to recover the transparency of the pipe 22 by removing volatile components attached to the surface of the pipe 22. Without unnecessarily stopping the production line,
The occurrence of defects due to insufficient curing can be prevented. The second method is a method in which when the intensity of the reflected ultraviolet light decreases to a predetermined value, the production linear velocity is reduced, and the irradiation time to the coating resin is extended to maintain substantially the same degree of curing. Third
The method of (1) uses the reflection intensity of ultraviolet light from
This is a method of controlling the output of the ultraviolet rays by feeding back to 1. According to the second and third methods, ultraviolet rays having a desired intensity are always supplied to the optical transmission wire passing through the pipe, and a predetermined cured state can be ensured.

FIG. 9 is a schematic diagram showing a control mechanism of the ultraviolet irradiation device. The reflection intensity of the ultraviolet light measured by the light receiving element 27 is fed back to the power source 31 of the light source 21 via the CPU 30. The CPU 30 has various conditions such as the number of cores of the optical fiber 2 forming the optical fiber ribbon 1, the type of the coating resin 3, the manufacturing speed, the type and the flow rate of the inert gas introduced into the pipe 22, and the like. Since it changes, data indicating the relationship between these conditions and the irradiation intensity of ultraviolet rays (see FIG. 8) is input in advance, and the output of the light source 21 is controlled based on these data.

Using the apparatus designed as described above, an optical fiber ribbon 1 in which four optical fiber strands 2 were coated with a urethane acrylate-based ultraviolet curable resin at a time was continuously manufactured. Even if volatile components adhere to the inner surface of the pipe 22 and the power supply 31 is adjusted so as to increase the output of the light source 21 even if the transmittance of ultraviolet rays decreases, the degree of cure of the coating resin 3 can be kept constant. did it.

FIG. 10 is a schematic diagram showing another control mechanism of the ultraviolet irradiation device. The ultraviolet light reflection intensity measured by the light receiving element 27 and the take-up speed of the capstan 18 measured by the speed sensor 32 are fed back to the power supply 31 via the CPU 30. The CPU 30 receives data on the intensity of ultraviolet irradiation, which is reduced due to the attachment of volatile components to the surface of the pipe 22, and the degree of curing, which is affected by the change in the amount of ultraviolet irradiation depending on the production linear speed of the optical fiber ribbon 1. The power supply 31 is adjusted so that the output of the light source 21 increases or decreases based on the data. This control method is necessary for manufacturing the optical fiber ribbon 1 having a predetermined degree of hardening even when the supply reel 10 or the take-up reel 20 is once reduced in speed and then replaced during continuous production.

The measurement of the ultraviolet light reflected from the surface of the pipe 22 is preferably performed by disposing the light receiving element 27 on the side of the pipe 29 for discharging the inert gas, as shown in FIG. The volatile components volatilized from the coating resin 3 are discharged along the flow of the inert gas, and a part of the volatile components is attached to the inner surface of the pipe 22, so that a large amount is attached to the discharge side. Therefore, the discharge pipe 29 side can be detected more reliably than the pipe 28 side into which the inert gas is introduced.

(Embodiment 2) In Embodiment 2, a case will be described in which a single optical fiber core is irradiated with ultraviolet rays and cured.

FIG. 11 is an overall configuration diagram showing an apparatus for manufacturing an optical fiber core. A feeder 40 provided to be movable up and down while holding the optical fiber preform 7;
Heating the tip of the optical fiber preform 7 introduced by
A drawing device 42 comprising a drawing furnace 41 for melting and drawing the optical fiber 6 is disposed. Immediately below the drawing device 42, a coating device 43 for coating the inner resin and the outer resin on the outer periphery of the optical fiber 6. An ultraviolet irradiation device 16 for irradiating the applied resin layer with ultraviolet rays to form the optical fiber core 5 immediately below the coating device 43, and an optical fiber core 5 below the ultraviolet irradiation device 16. The apparatus includes a capstan 44 for drawing at a constant speed, and a device 45 for winding the drawn optical fiber 5 onto a reel.

The ultraviolet irradiation device 16 has the same configuration as that shown in FIG. 2. In FIG. 2, a pipe 22 through which the optical fiber core 5 is passed together with an inert gas for cooling and which has good ultraviolet transmission, and A light source 21 for irradiating and curing the ultraviolet curable resin which is disposed outside and coats with ultraviolet light.
And an elliptical reflecting mirror 23 having two focal points. At the focal points of the reflecting mirror 23, a light source 21 and a pipe 22 are provided, respectively, and housed in a housing 24. Further, the reflecting mirror 23
Holes 25a and 25b are formed in the housing 24, respectively, to form a cylindrical measurement hole 25 for introducing ultraviolet light.
A shutter 26 that opens and closes on the outer wall of the housing b to transmit and block ultraviolet rays, and a light receiving element 27 is provided outside the shutter 26, and a light receiving surface of the light receiving element 27 has a predetermined position with respect to the axial direction of the measurement hole 25. Adjusted to the angle and fixed.

FIG. 12 is a perspective view showing an example of the configuration of an optical fiber core. The optical fiber core 5 is formed on the outer periphery of a quartz glass fiber 6 with a coating resin 3 composed of an inner resin and an outer resin. As the coating resin 3, a urethane acrylate-based ultraviolet curable resin or a silicone resin is used.

Also in this embodiment, FIGS.
As in the case shown in (1), the intensity of the ultraviolet light reflected from the pipe 22 is measured and fed back to the ultraviolet light source 21 to control the output of the light source 21 so that the optical fiber 1 is stably cured for a long time. be able to. The action of curing the resin 3 coated on the outer periphery of the optical fiber 5
The effect is the same as that of the first embodiment.

[0039]

According to the production method of the present invention, even if the volatile component volatilized from the coating resin adheres to the inner surface of the pipe with the passage of time and the ratio of ultraviolet rays transmitted through the pipe decreases, Since UV reflection from the surface is measured, the production line is not unnecessarily stopped, and the occurrence of defective products due to insufficient curing can be prevented.

Further, by controlling the output of the light source based on the measured ultraviolet reflection from the pipe surface,
Ultraviolet light of a desired intensity is always supplied to the optical transmission wire passing through the pipe, and a predetermined cured state can be ensured.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an apparatus for manufacturing an optical fiber ribbon.

FIG. 2 is a plan view (a) and a front view (b) showing a configuration of an ultraviolet irradiation device.

FIG. 3 is a plan view showing another configuration of the ultraviolet irradiation device.

FIG. 4 is a perspective view showing a configuration of an optical fiber ribbon.

FIG. 5 is a diagram showing a flow path of an inert gas.

FIG. 6 is a diagram showing a path on which ultraviolet light is reflected on a pipe surface.

FIG. 7 is a diagram illustrating a method of receiving ultraviolet light reflected on a pipe surface.

FIG. 8 is a graph showing a change in a relative value of an ultraviolet irradiation intensity and a relative degree of curing of a coating resin.

FIG. 9 is a schematic view showing a control mechanism of the ultraviolet irradiation device.

FIG. 10 is a schematic view showing another control mechanism of the ultraviolet irradiation device.

FIG. 11 is an overall configuration diagram showing an apparatus for manufacturing an optical fiber core.

FIG. 12 is a perspective view showing a configuration of an optical fiber.

FIG. 13 is a configuration diagram showing a conventional manufacturing apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical fiber tape core wire (light transmission wire), 2 ... Optical fiber strand, 3 ... Coating resin, 4 ... Volatile component, 5 ...
Optical fiber core wire (wire material for optical transmission), 6 ... optical fiber,
7 ... optical fiber preform, 10 ... supply reel, 11 ...
-Dancer roller for supply tension control, 12: Guide roller, 13: Guide roller with groove, 14: Coating device, 1
5 ... resin supply tank, 16 ... ultraviolet irradiation device, 17 ...
・ Inert gas supply tank, 18 ... capstan, 19 ...
A take-up tension control dancer roller, 20 a take-up reel, 21 a light source, 22 a pipe, 23 a reflecting mirror, 2
4 ... Case, 25 ... Measurement hole, 26 ... Shutter, 27 ...
Light-receiving elements, 28, 29 ... piping, 30 ... CPU, 31 ...
・ Power supply, 32 ・ ・ ・ Speed sensor, 40 ・ ・ ・ Feed device, 41 ・ ・ ・
Drawing furnace, 42 ... drawing device, 43 ... coating device, 44 ...
Capstan, 45 ... take-up reel, f ... focus, U ...
・ UV

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kaoru Okuno 1, Tayacho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Sumitomo Electric Industries, Ltd. Yokohama Works (72) Inventor Saburo Kawabata 1, Tayacho, Sakae-ku, Yokohama-shi, Kanagawa Sumitomo Ken Kogyo Co., Ltd. Yokohama Works (72) Inventor Takeshi Ken Takahashi 1 Tagamachi, Sakae-ku, Yokohama, Kanagawa Prefecture Sumitomo Electric Co., Ltd. Yokohama Co., Ltd. (72) Inventor Ryohide Oka 1 Tayacho, Sakae-ku, Yokohama, Kanagawa Prefecture Sumitomo Electric Manufacturing Co., Ltd.

Claims (6)

[Claims] 1. An optical transmission wire coated with an ultraviolet-curable coating resin is passed through a pipe that transmits ultraviolet light together with an inert gas, and ultraviolet light output from a light source is irradiated from outside the pipe. In the method for manufacturing an optical transmission wire to cure the coating resin, receiving the ultraviolet light reflected on the surface of the pipe,
A method for manufacturing a wire for optical transmission, comprising measuring a reflection intensity of the ultraviolet ray, which changes because a volatile component volatilized from the coating resin adheres to an inner surface of the pipe with the passage of time. 2. A method for measuring the reflection intensity of ultraviolet light, wherein the measurement is performed through a cylindrical measurement hole whose axial direction can be adjusted on a plane orthogonal to the longitudinal direction of the pipe while facing the pipe. The method for producing an optical transmission wire according to claim 1, wherein: 3. The optical transmission method according to claim 2, wherein in the method of measuring through the measurement hole, a shutter provided in the measurement hole is opened and closed every desired time to perform intermittent measurement. Method of manufacturing wire rods. 4. The optical transmission wire according to claim 1, wherein production conditions are adjusted and processed so that the coating resin has a predetermined degree of curing based on the measured reflection intensity of the ultraviolet light. Manufacturing method. 5. The method of adjusting and processing the manufacturing conditions,
The optical transmission device according to claim 4, wherein a volatile component attached to the inner surface of the pipe is treated, or a production linear speed of the optical transmission wire is adjusted, or an output of the light source is controlled. Wire rod manufacturing method. 6. The method of controlling the output of the light source according to claim 5, wherein the control is performed based on the measured reflection intensity of the ultraviolet ray and a production linear speed of the optical transmission wire.
3. The method for producing a wire for optical transmission according to claim 1.