JPH06144881A - Curing device for coating agent applied on optical fiber - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] In a curing device for a coating agent applied to an optical fiber, the surface temperature of a lamp is uniformly cooled and the wavelength of emitted light is stabilized without changing. A microwave cavity 6 is formed by a reflecting mirror 13, an electrodeless lamp 12 is arranged at a first focal point of the microwave cavity 6, and a second cavity is formed.
An optical fiber F coated with a coating agent is arranged at the focal point, and the lamp is rotated about the longitudinal direction while blowing cooling air from a predetermined direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curing device for an ultraviolet curable coating agent applied to an optical fiber.

[0002]

2. Description of the Related Art A UV-curable coating agent (hereinafter, also simply referred to as "coating agent") is applied to the outer surface of an optical fiber in order to prevent damage to the outer surface of the optical fiber or to bundle a plurality of optical fibers. is doing. The coating agent is applied in an uncured state by a coating device and is cured by a coating agent curing device (hereinafter, also simply referred to as “curing device”).

FIGS. 5A and 5B show an example of a conventional curing device. (A) is a side sectional view of the curing device, and (b) is a plan view taken along the line AA of (a). The optical fiber F coated with the ultraviolet curable coating agent travels through the light-transmitting pipe 51 from the upper side to the lower side. A mercury lamp 52 that mainly emits ultraviolet rays;
The reflecting mirror 53 fixed to the casing 54 constitutes a light irradiation mechanism. A connector cap 55 is provided at the lower end of the translucent pipe 51 so as to close its opening, and a connector cap 56 is provided at the upper end thereof so as to close the opening. The translucent pipe 51 is fixed to the casing 54 via a connector cap 55 and a connector cap 56. Then, each connector cap has a through hole along the traveling path of the optical fiber F.

The reflector 53 has an elliptic cylindrical shape whose inner surface is a mirror surface. The mercury lamp 52 is placed on the first focus of the reflecting mirror 53.
Is located, and a traveling path of the optical fiber F is formed on the second focal point. Since the reflecting mirror 53 is a cylindrical body, the mercury lamp 52 is also a straight tube type lamp. A coating device (not shown) is provided above the curing device, and an uncured coating agent is applied to the outer surface of the optical fiber F by the coating device. The optical fiber F coated with the uncured coating agent is introduced into the translucent pipe 51 from the through hole of the connector cap 56 and travels from above to below inside the translucent pipe 51.
It is discharged from the through hole of the connector cap 55. Then, while the optical fiber F travels inside the translucent pipe 51, the uncured coating agent is irradiated with the ultraviolet rays from the mercury lamp 52 and the reflecting mirror 53 to cure the coating agent. For example, Japanese Patent Publication No. 3-49625 is a disclosure of this technique.

As a light source for emitting ultraviolet rays, in addition to the mercury lamp, an electrodeless lamp having no electrode is used. This lamp is a magnetron (microwave generating means) that is filled with a light-emitting material such as mercury and is placed outside the reflecting mirror.
Illuminates the lamp with microwaves. This irradiation causes the lamp to emit ultraviolet light when the luminescent material is excited. With an electrodeless lamp, the diameter of the tube can be reduced as much as there are no electrodes. When the tube diameter is reduced, the light source is concentrated on the first focus, and the object (optical fiber) on the second focus can be strongly irradiated. When the irradiation on the second focus is concentrated and the intensity becomes high, the curing speed of the coating agent is accelerated, and as a result, the traveling speed of the optical fiber can be further increased. For example, JP-A-62-229202 discloses this technique.

Furthermore, recently, it is required to carry out the curing treatment of the coating agent applied to the optical fiber faster. However, there is a problem in the method of reducing the lamp diameter. When the tube diameter of the lamp is made thin, the temperature per unit surface area of the lamp becomes high. When the temperature exceeds the heat resistant temperature of the glass tube, the glass tube becomes devitrified (whitens,
It loses transparency) and changes its shape. In general,
In order to deal with this problem, do not exceed the heat resistant temperature,
The lamp is cooling. For example, there is a method in which a small opening that does not allow microwaves to leak is provided in a part of the reflecting mirror and cooling air is blown to the lamp from the outside through this opening. Then, as the surface temperature becomes higher, it becomes necessary to improve the blowing ability of the cooling air or to provide more cooling openings. However, each of the methods involves problems such as an increase in the size of the device, a complicated structure, and a reduction in the ultraviolet ray irradiation amount on the reflecting mirror. Also,
Even if these methods can be achieved, they only partially cool the hot lamp surface, resulting in a temperature difference at the lamp surface. If there is a temperature difference on the surface of the lamp,
Since the encapsulating metal collects in the lower temperature without evaporating, it does not contribute to the emission spectrum of the encapsulating metal. And it affects the emission wavelength.

[0007]

SUMMARY OF THE INVENTION The problem to be solved by the present invention is to provide a curing device for a UV-curable coating agent applied to an optical fiber, which has a long length in order to increase the illuminance to be irradiated. In reducing the tube diameter of the electrodeless type light emitting lamp, the surface temperature of the lamp generated at this time can be uniformly cooled, and stable light emission can be performed without changing the wavelength of the emitted light. .

[0008]

In order to solve the problems, the present invention relates to a reflecting mirror having an elliptic cylindrical shape whose inner surface is a mirror surface and a part of its inner space also forms a microwave cavity. A long electrodeless type ultraviolet light emitting lamp located on the first focal point of the reflecting mirror and an optical fiber coated with the ultraviolet curing coating agent which runs on the second focal point of the reflecting mirror. Scale transparent pipe, microwave generating means provided outside the reflecting mirror, microwave coupling means for coupling the microwave generated by the microwave generating means to the electrodeless ultraviolet light emitting lamp, and the reflecting mirror Of the electrodeless type ultraviolet light emitting lamp, and a rotating means for rotating the electrodeless type ultraviolet light emitting lamp about its longitudinal axis. To.

[0009]

With such a structure, cooling air is blown along the longitudinal direction of the long electrodeless type ultraviolet light emitting lamp and is rotated about the longitudinal direction, so that the tube diameter of the lamp can be reduced. The surface area can be cooled almost uniformly. Therefore, the lamp can stably emit light without changing its radiation wavelength.

[0010]

[Examples] Hereinafter, specific examples will be described. FIG. 1 corresponds to FIG. 5 and shows an embodiment of the curing apparatus of the present invention. (A) is a side sectional view of the curing device, and (b) is a plan view taken along the line AA of FIG. 11
Shows a translucent pipe corresponding to 51 in FIG.
12 indicates a lamp corresponding to 52 in FIG. However, in FIG. 5, in contrast to the mercury lamp with electrodes,
Reference numeral 2 denotes an electrodeless type ultraviolet light emitting lamp. 13 is shown in FIG.
5 shows a reflecting mirror having an elliptic cylindrical shape corresponding to 53 in FIG. The elliptical reflecting mirror 13 is divided into two, unlike FIG. 14 shows a casing corresponding to 54 in FIG. Reference numerals 15 and 16 denote connector caps corresponding to 55 and 56 in FIG. 5, respectively. Since the description of each operation is the same as that of FIG. 5, the description is omitted.

The electrodeless ultraviolet light emitting lamp 12 (hereinafter also referred to as a lamp) has a long glass tube filled with a light emitting material such as mercury. Then, it may function as a metal halide lamp by enclosing a metal such as iron, tin, or cobalt. The lamp 12 has, for example, a length of 258 mm,
An inner diameter of 4 mm and an outer diameter of 6 mm are applied. Reflector 13
Has an elliptic cylindrical shape, and the space formed therein is composed of the measuring part 131, the upper part 132, the lower part 133 and the mesh 134, and also forms the microwave cavity 6.
The measuring unit 131 is composed of a dielectric mirror, and a vapor deposition film of metal oxide is formed as a reflecting surface on a glass substrate. The upper part 132 and the lower part 133 are made of aluminum and similarly have a function of reflecting ultraviolet rays. Mesh 13
No. 4 is made of stainless steel mesh and transmits ultraviolet rays,
Microwaves are not transmitted. The magnetron 60 is an example of microwave generation means, and generates about 1500 watts of microwave power having a frequency of 2450 MHz. The microwave is coupled to the microwave cavity 6 via the waveguide 61 and the antenna 62 as the microwave coupling means.

FIG. 2 shows a forced cooling system including a curing device applied to the optical fiber shown in FIG. Before and after the curing device 2, blower pipes 21 and 22 for sending cooling air into the curing device are connected. The cooling air generated from the cooling fan 20 is blown into the blower pipe 2 through the blower duct 201.
Sent to 1. A power supply 211 is arranged in the blower pipe 21. The power source 211 relates to the magnetron 60 and a lamp rotating mechanism described later. When entering the curing device 2, the cooling air flows in a specific direction by the regulating members 23 and 24.
Cooling fins 25 are arranged around the magnetron 60 to enhance the cooling effect of the magnetron 60. After passing through the magnetron 60, the cooling air cools the light irradiation mechanism. Then, the air is exhausted from the blower duct 221 via the blower pipe 22.

FIG. 3 shows an elliptic cylinder-shaped dielectric mirror 13.
Is shown. A plurality of vent holes 30 are provided in the side portion 131 on the back side of the translucent pipe 11 and along the longitudinal direction of the lamp. The vent holes 30 are densely provided at positions corresponding to the ends of the lamp, and are sparsely provided closer to the central portion. The cooling air that has passed through the ventilation holes 30 is the light emitting portion of the lamp 12 and the light-transmitting pipe 1.
Spray only the back side for 1. The position where the cooling air is blown to the lamp 12 is preferably on the back side from the viewpoint of reflection of ultraviolet rays, but if the function of the dielectric mirror 13 to reflect ultraviolet rays is not impaired and the irradiation target can be satisfactorily irradiated, It can be sprayed from other directions. The size of the vent hole 30 is not particularly limited as long as the dielectric mirror 13 does not impair the function of reflecting ultraviolet rays. An example is 16 to 36 mm ² . Also,
Regarding the balance of the number of the ventilation holes 30 in the longitudinal direction, it is not always necessary that the end portions are densely arranged and the central portion is sparse. Reference numeral 31 is an opening through which the antenna 62 is inserted, but it can also be used as a ventilation hole for cooling air by an amount larger than the diameter of the antenna 62. These ventilation holes 30
The cooling means is constituted by.

FIG. 4 shows the rotating means of the lamp 12. A holding portion 40 is formed at the upper end of the lamp 12 arranged in the vertical direction, following the light emitting portion, and a holding portion 41 is also formed at the lower end. The tip of the holding portion 40 is in contact with the driven shaft member 42, is in pressure contact with the spring member 44, and is rotated by a bearing 43 with a low load. The tip of the holding portion 41 is in contact with the contact portion 46 of the drive shaft member 45. Due to the action of the spring member 44, this portion is also in pressure contact. The inner surfaces of both the driven shaft member 42 and the contact portion 46 are concave and have a structure that facilitates centering. Reference numeral 47 is a motor, and 48 is a gear box having a gear therein. When the motor 47 rotates, the gear box 48
A predetermined number of rotations is converted by a plurality of gears inside to rotate the drive shaft member 45. Due to the rotation of the drive shaft member 45, the lamp 12 also rotates about the longitudinal direction.

As described with reference to FIG. 3, the cooling air is generated by the lamp 1.
2 is sprayed from a predetermined direction, the lamp 12
By rotating, the surface will be sprayed uniformly. The rotation of the lamp is, for example, 2 rotations / second. The rotating means is not limited to the embodiment. However,
In the case of the rotating means shown in this embodiment, the lamp can be easily replaced, especially because of the holding structure of the lamp. Further, since the lamp of the present invention is an electrodeless type, no electrical connection is required and the structure for rotating the lamp is extremely simple.

[0016]

As described above, according to the apparatus for curing a coating agent applied to an optical fiber of the present invention, cooling air can be blown along the longitudinal direction of a long electrodeless type ultraviolet light emitting lamp. Since it can be rotated about its longitudinal direction as an axis, the surface area can be cooled substantially uniformly even if the tube diameter of the lamp is reduced. Therefore, the lamp can stably emit light without changing its radiation wavelength.

[Brief description of drawings]

FIG. 1 is a schematic view of an embodiment of a curing device for a coating agent applied to an optical fiber according to the present invention.

FIG. 2 is a schematic view of an embodiment of a forced cooling system for a curing device for a coating agent applied to an optical fiber according to the present invention.

FIG. 3 is a schematic view of an embodiment of a reflection mirror having an elliptic cylindrical shape of a curing device for a coating agent applied to an optical fiber according to the present invention.

FIG. 4 is a schematic view showing an embodiment of a lamp rotating means in a curing device for a coating agent applied to an optical fiber according to the present invention.

FIG. 5 is a view showing a conventional apparatus for curing a coating agent applied to an optical fiber.

[Explanation of symbols]

 11 Translucent Pipe 12 Electrodeless Ultraviolet Light Emitting Lamp 13 Reflection Mirror 14 Casing 20 Cooling Fan 21 Blower Tube 22 Blower Tube 45 Drive Shaft Material 47 Motor 60 Microwave Generation Means 62 Microwave Coupling Means

Claims (1)

[Claims] 1. A reflecting mirror having an elliptic cylindrical shape, the inner surface of which is a mirror surface and a part of the inner space of which also forms a microwave cavity, and a long elongated member which is located on the first focal point of the reflecting mirror. An electrodeless type ultraviolet light emitting lamp, a long translucent pipe that is placed so as to surround an optical fiber coated with an ultraviolet curing type coating agent that runs on the second focal point of the reflecting mirror, and is provided outside the reflecting mirror. The microwave generating means and the microwave coupling means for coupling the microwave generated by the microwave generating means to the electrodeless ultraviolet light emitting lamp, and the cooling air taken in from the outside of the reflecting mirror, and the electrodeless ultraviolet light emitting lamp Coating means applied to the optical fiber, which comprises a cooling means for spraying at a predetermined position on the optical fiber and a rotating means for rotating the electrodeless type ultraviolet light emitting lamp about its longitudinal direction. Curing device.