JPH07311316A - Recoating method of optical fiber juncture and mold device used in this method - Google Patents

Abstract

PURPOSE:To provide a method for recoating the juncture of optical fibers with a photosetting resin in a bubbleless state at the time of using this resin as a recoating material and reinforcing the juncture by molding and a mold device used in this method. CONSTITUTION:This method for recoating the juncture of the optical fibers comprises discharging the air bubbles contained in the photosetting resin and curing the photosetting resin by controlling the heating of molds 13, thereby controlling the viscosity of the photosetting resin at the time of molding the photosetting resin in the juncture of the optical fibers set in recoating grooves 33, 41 of the molds 13, then curing the photosetting resin by irradiating the photosetting resin with light for curing. This mold device is constituted by providing a heat source 25 for controlling the heating of the molds 13 in order to control the viscosity by controlling the temp. of the photosetting resin in the molds 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recoating method for reinforcing a spliced optical fiber connecting portion and a mold type apparatus used in the method. More specifically, the present invention relates to a photocuring resin (UV curing type). TECHNICAL FIELD The present invention relates to a method for performing recoating without bubbles when a resin) is molded as a recoating agent in an optical fiber connecting portion and cured, and a mold type device used in the method.

[0002]

2. Description of the Related Art As a method for connecting optical fibers to each other, there is a fusion splicing for permanent connection. In the fusion spliced portion of the optical fiber, the coating material is already removed, so that it is necessary to reinforce the optical fiber or the optical fiber with the coating material.

As an example of reinforcing the above-mentioned connecting portion of the optical fiber, the connecting portion of the optical fiber is set in the recoat groove of the mold having the upper die and the lower die, and the connecting portion of the optical fiber is optically coated with the recoating agent. There is a method in which after the curable resin is molded, the photocurable resin is irradiated with curing light to be cured.

[0004]

As described above, in the structure in which the connecting portion of the optical fiber is reinforced by the remolding agent using the mold, the temperature of the recoating agent supplied to the mold is affected by the outside air temperature, and the recoating agent is used. Since the viscosity of the agent changes, the behavior of the flow of the recoat agent in the recoat groove of the mold changes.

Therefore, depending on the viscosity of the recoating agent, as shown in FIG. 5, the recoating agent 3 is sufficiently filled in the deep part of the optical fiber 1 between the core 1A and the coating 1B. It may not be possible to generate bubbles 5.

Further, there is a problem that gas may be entrained when the recoating agent is filled in the connecting portion of the optical fiber.

[0007]

The present invention has been made in view of the conventional problems as described above, and a method of recoating an optical fiber connecting portion according to the present invention is a recoating method for a mold including an upper mold and a lower mold. After setting the optical fiber in the groove and molding the photo-curable resin into the connection part of the optical fiber, the photo-curable resin is irradiated with curing light to cure the photo-curable resin. As a method of recoating the fiber connecting portion, the mold is heated and controlled to control the viscosity of the photo-curable resin in the mold, and the bubbles contained in the photo-curable resin are discharged to cure the photo-curable resin. This is a method of recoating an optical fiber connection portion for curing a resin.

The mold die apparatus is a mold die apparatus having an upper die and a lower die, and at least one of the die is transparent, and a recoat groove for setting an optical fiber at the joint between the upper die and the lower die. And a gate for supplying the photocurable resin into the recoat groove and a gas vent passage for venting gas in the recoat groove, and the temperature is controlled by controlling the temperature of the photocurable resin in the mold. In order to control the temperature, a heat source for heating and controlling the mold is provided.

The heat source is provided in a positioning block on which the mold is placed, and heat is conducted from the positioning block to the mold.

[0010]

With the above structure, when the optical fiber connecting portion is set in the remolding groove of the mold in the molding apparatus and the recoating agent is filled in the connecting portion, the mold is heated and controlled by the heat source. The temperature of the recoating agent thus prepared can be controlled, and the viscosity of the recoating agent can be optimally controlled.

Therefore, the recoating agent can be sufficiently filled up to the depth of the step portion between the core of the optical fiber and the coating material, and the generation of bubbles in the portion can be prevented.

Further, when bubbles are generated during the filling of the recoating agent, the temperature of the recoating agent is raised to reduce the viscosity, so that the portion in which the bubbles are mixed can be smoothly discharged, and there is no bubbles. In this state, the recoating agent can be cured.

[0013]

EXAMPLE At the connecting portion of the optical fiber 1 shown in FIG.
For example, a mold type device 7 for filling a recoating agent 3 of a photocurable resin such as an ultraviolet curable epoxy acrylate resin is constructed as shown in FIGS.

In outline, the mold die device 7 includes a positioning block 11 provided on a base 9 and a mold die 1
3 is placed.

More specifically, the base 9 has a groove shape with a stopper portion 15 at the tip and a rising portion 17 on the opposite side, and the base 9 has a light source (located below). A transmission hole 21 through which light (ultraviolet light) from the ultraviolet light source 19 can be transmitted is formed.

The positioning block 11 is arranged in the groove of the base 9 and positioned by contacting the stopper portion 15. The positioning block 11 has an L-shape having a rising portion 23 that is in contact with the stopper portion 15. The rising portion 23 is provided with a suitable heat source 25 such as a heater over almost the entire width. is there. An appropriate temperature sensor 27 such as a thermistor or a thermocouple is provided at a position close to the heat source 25 or at the heat source 25.

Further, the positioning block 11 is transparent or partially provided with a transmission hole (not shown) so that the light transmitted through the transmission hole 21 reaches the mold 13.

The heat source 25 is for controlling heating of the mold 13 mounted on the positioning block 11, and is temperature controlled by an appropriate control device (not shown) such as a microcomputer. is there.

The temperature of the heat source 25 is the temperature sensor 27.
Detected and is fed back to the control device.

The mold die 13 is composed of a transparent upper die 29 and a transparent lower die 31 made of, for example, quartz glass, which are vertically joined to each other. Has a recoat groove for setting the connecting portion of the optical fiber 1.

More specifically, all the ridges of the lower mold 31 made of quartz glass are appropriately chamfered to prevent chipping, and the upper surface of the lower mold 31 (joint surface with the upper mold 29). ), A recoat groove 33 having a semicircular cross section for setting the connection portion of the optical fiber 1 is formed over the entire length in the longitudinal direction.

A gate 37 connected to the injection port 35 of the photocurable resin is connected to the central portion of the recoat groove 33 in the longitudinal direction.

A groove 39A for a gas vent passage is provided on the joint surface of the lower die 31 in parallel with the recoat groove 33 over the entire length, and the groove 39A is formed with the recoat groove 33 in between. Grooves 39B, 39 for the gas vent passage on the opposite side
C is provided.

All the ridges of the upper die 29 are in the lower die 31.
Similarly, appropriate chamfering is performed. As shown in FIG. 4, on the lower surface of this upper die 29 (the surface to be joined with the upper surface of the lower die 31), there is provided a semi-arc shaped recoat groove 41 facing the recoat groove 33 of the lower die 31, along the entire length in the longitudinal direction. It is formed over.

The lower die 31 is attached to the joining surface of the upper die 29.
The groove 43A for the gas vent passage corresponding to the groove 39A is formed over the entire length, and the central portion in the longitudinal direction of the groove 43A and the central portion in the longitudinal direction of the recoat groove 41 have a width of 1 mm.
They are connected by a shallow communication groove 45A of about 3 mm and are connected by a communication groove 45B at symmetrical positions 4 to 6 mm apart from the communication groove 45A on both sides.

Further, on the joining surface of the upper mold 29, a groove 43 for a gas vent passage corresponding to the grooves 39B and 39C of the lower mold 31.
B and 43C are formed, and each of the grooves 43B and 43C is in communication with the recoat groove 41 by a communication groove 45C.

On the upper surface of the upper mold 29, as shown in FIG. 1, the light from the light source 19 which has passed through the lower mold 31 and the upper mold 29 is reflected so as to be focused on the recoat grooves 33 and 41. A reflecting plate 49 having a concave reflecting surface 47 is placed.

In the above configuration, the optical fiber 1
In order to mold and reinforce the connection portion of the lower mold 3 with the recoating agent 3, first, the upper mold 29 is removed from the lower mold 31 and the lower mold 3 is removed.
The optical fiber 1 is set in the recoat groove 31 in 1. In this case, the central portion of the connecting portion of the optical fiber 1 is set so as to be positioned corresponding to the gate 37.

After that, the upper mold 29 is placed and fixed on the lower mold 31, and the optical fiber 1 is clamped and fixed between the recoat grooves 41 and 33 of the upper and lower molds 29 and 31.

After the upper mold 29 is placed and fixed on the lower mold 31 as described above, when the recoating agent 3 is press-fitted from the injection port 35 provided in the lower mold 31, the recoating groove 3 is passed through the gate 37.
It flows into the inside of 3, 41 and is filled in the portion of the connecting portion of the optical fiber 1.

When the recoating agent 3 is filled as described above, the gas in the recoating grooves 33 and 41 is connected to the communicating grooves 45A and 4A.
5B, 45C through grooves 39A, 39B, 39C; 43
It is discharged to A, 43B and 43C. Also, the upper and lower molds 2
9 and 31 are heated to 30 ° C. to 60 ° C. by the heat source 25 to prevent the temperature of the filled recoating agent 3 from decreasing and the viscosity from increasing.

That is, the temperature of the recoating agent 3 in the upper and lower molds 29 and 31 is controlled to 30 ° C. to 60 ° C.
The viscosity of the recoating agent 3 is kept small, and the recoating agent 3 is spread deep into a large step portion between the core 1A of the optical fiber 1 and the coating material 1B to prevent bubbles from being generated in the portion.

When bubbles are present when the recoating agent 3 is filled, the recoating agent 3 is passed through the communicating grooves 45A, 45B, 4
By vigorously overflowing to the groove 39A to 39C; 43A to 43C side through 5C, it is possible to discharge the portion in which the bubbles are mixed, and it is possible to make the state in which there are no bubbles.

By the way, in order to reduce the viscosity of the recoating agent 3, the recoating agent 3 is heated to 30 ° C. to 60 ° C. by the heat source 25. However, if it is heated to 60 ° C. or higher, the curing of the recoating agent (resin) 3 proceeds. If the temperature is 30 ° C. or lower, the viscosity is high and the recoating agent 3 in the recoating groove
Filling work becomes difficult. Therefore, it is desirable to control the temperature of the recoating agent 3 to about 30 ° C to 60 ° C.

As described above, in a state where the bubbles are discharged from the recoating agent 3 in the connection portion of the optical fiber 1, the recoating agent 3 is irradiated with curing light from the light source 19 to cure the recoating agent 3. Thus, the connection portion of the optical fiber 1 is reinforced in a state where there are no bubbles in the recoating agent 3.

In the above embodiment, the heat source 25 is provided at the rising portion 23 of the positioning block 11; however, the heat source 25 of the positioning block 11 is positioned below the lower die 31. It may be provided on the lower side. In some cases, the upper and lower molds 29, 31
It is also possible to provide it at an appropriate position such as one or both side surfaces. That is, the heat source 25 can be provided at any position.

[0037]

As will be understood from the above description of the embodiments, according to the present invention, when the recoating agent is injected and filled into the mold, the gas in the mold is effectively discharged from the gas vent passage. It can be discharged and the temperature and viscosity of the filled recoating agent can be controlled by heating and controlling the upper and lower molds, and recoating can be performed deep inside the large step between the optical fiber core wire and the coating material. It is possible to spread the agent, and it is possible to prevent bubbles from being generated in the relevant portion.

Further, since the viscosity of the recoating agent can be controlled and the recoating agent can overflow from the degassing passage of the mold die, when bubbles exist in the recoating agent, the mixed portion of the bubbles is effective. The recoating agent can be discharged, and the recoating agent can be cured with no bubbles in the recoating agent.

[Brief description of drawings]

1 is a cross-sectional view taken along line I-I of FIG. 2, showing a mold apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective explanatory view of a mold apparatus according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a lower mold.

FIG. 4 is an explanatory diagram of an upper die.

FIG. 5 is an explanatory diagram of a connecting portion of an optical fiber.

[Explanation of symbols]

 1 Optical Fiber 3 Recoating Agent 7 Mold Type Device 11 Positioning Block 13 Mold Type 19 Light Source 25 Heat Source 29 Upper Mold 31 Lower Mold 33,41 Recoat Groove 39,43 Groove 45A, B Communication Groove

Claims (3)

[Claims] 1. An optical fiber is set in a recoat groove in a mold having an upper die and a lower die, and a photocurable resin is molded on a connecting portion of the optical fiber, and then cured to the photocurable resin. The method of recoating the connection part of the optical fiber by irradiating the light to cure the photocurable resin, and controlling the viscosity of the photocurable resin in the mold by controlling the heating of the mold. A method for recoating an optical fiber connecting part, characterized in that air bubbles contained in the photocurable resin are discharged to cure the photocurable resin. 2. A molding die apparatus comprising an upper die and a lower die, at least one of which is transparent, and a recoat groove for setting an optical fiber is provided at a joint between the upper die and the lower die. A gate for supplying the photocurable resin into the recoat groove and a gas vent passage for venting the gas in the recoat groove are provided, and the temperature of the photocurable resin in the mold is controlled to control the viscosity. Therefore, a mold device is provided with a heat source for heating and controlling the mold. 3. The mold according to claim 2, wherein the heat source is provided in a positioning block on which the mold is placed, and heat is conducted from the positioning block to the mold. apparatus.