JPS6245522B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a device for finishing the end face of a plastic optical fiber.

[Background Art] Conventionally, as shown in FIG. 1, this type of end face finishing apparatus for a plastic optical fiber presses the upper surface 2a of a heated forming jig 2 onto the end face 1a of a plastic optical fiber 1 to finish the end face 1a. The molding jig 2 is formed by a heating part 3 with a built-in heater and a molding part 5 made of a glass plate attached to the top surface of the heating part 3 with an adhesive 4. The upper surface 2a of the molding part 5 is a flat mirror molding surface. In the figure, 6 is a chuck part that chucks the optical fiber 1 to the guide ring 7.
By rotating the cap 8 clockwise, the optical fiber 1 is held under pressure by the gripping portion 9. Reference numeral 10 denotes a deburring ring, the lower part of which is conical and the lower edge of the optical fiber insertion hole 10a is blade-shaped. When the surface comes into contact with the lower edge of the optical fiber insertion hole 10a, the optical fiber 1
The burr formed on the periphery of the end face 1a of the plate is cut out. Reference numeral 11 denotes a cooling medium injection port, and the heat-formed part is forcibly cooled by the cooling medium such as air injected from this injection port 11. 12 is a vice for fixing the forming jig 2. The optical fiber 1 is set so as to slightly protrude from the lower edge of the optical fiber insertion hole 10a of the deburring ring 10, and the amount of protrusion is adjusted using a spacer 13.

By the way, in such a conventional example, the upper surface 2a of the molding jig 2, that is, the molding surface, is a flat mirror surface, so the end surface 1a of the optical fiber 1 is
As shown in Figure a, it is formed into a flat surface when heated. However, when this heat-formed part is cooled, the center of the end surface 1a becomes depressed as shown in FIG. There was a problem that the end surface 1a became a concave curved surface. That is, in this type of end finishing device, the optical fiber 1 is cut into a burring ring 10.
Since the end surface 1a of the optical fiber 1 is heated when the end surface 1a of the optical fiber 1 is gripped, the heat dissipation from the outer periphery of the end surface 1a of the optical fiber 1 becomes larger than the heat dissipation from the center, and the temperature rise rate at the end surface periphery ( heating rate)
is smaller than that at the center, and the amount of thermal expansion at the outer periphery is smaller than that at the center. Therefore, when the end face 1a of the optical fiber 1 is heat-molded with a flat molding surface in such a thermally expanded state, the amount of contraction during cooling is larger at the center than at the outer periphery, so that the optical fiber The end surface 1a of 1 is
As shown in FIG. 4, this results in a concave curved surface with a concave central portion (the amount of shrinkage is indicated by an arrow).
In addition, the rate of temperature fall (cooling rate) during the cooling process is faster at the outer periphery than at the center due to heat dissipation by the deburring ring 10, and solidification starts from the outer periphery and gradually progresses to the center. During the shrinkage process during cooling, the radial shrinkage of the heat-formed portion is suppressed and most of the shrinkage occurs in the axial direction, resulting in a larger amount of shrinkage in the central portion.

As mentioned above, in the conventional example, although the end surface 1a is heat-formed into a flat surface, the end surface 1a after cooling is
A becomes a concave curved surface, resulting in a problem that the connection loss of the optical fiber 1 becomes large.

[Object of the Invention] The present invention has been made in view of the above-mentioned points, and the object thereof is to easily finish the end face of a plastic optical fiber, and to provide a plastic optical fiber that shrinks when cooled. To provide an end face finishing device which can easily finish an end face into a flat surface.

[Disclosure of the Invention] (Embodiment) FIGS. 5 to 7 show an embodiment of the present invention, in which a burring ring 10 is inserted into the end of a plastic optical fiber 1.
The molding surface of the heated molding jig 2 is pressed against the end surface 1a of the optical fiber 1 protruding from the burring ring 10 until it comes into contact with the deburring ring 10, and the end surface 1a is heated and molded. In the end face finishing apparatus similar to the conventional example using the tool 2, a cooling means 15 is provided for cooling the heat-formed part centered on the central part of the end face 1a. It is composed of a cooling medium circulation hole 16 provided, a cooling rate regulator 17, and a pipe 18. The cooling medium such as air injected from the injection port 19 is guided to the radial cooling part 16a through the introduction part 16a, and is formed by a radial cooling part 13a provided directly below the molding part 5. The system is designed to mainly cool the air. That is, the heat-formed end surface 1a of the optical fiber 1 is cooled centering on the central portion. In the figure, 20 is a cooling medium discharge hole, and 21 is a heater.

Now, when cooling is performed centering on the central portion of the end surface 1a of the optical fiber 1, cooling of the central portion of the end surface 1a, where the cooling rate conventionally has been slowest, is accelerated by the heat dissipation by the burring ring 10. As a result, the temperature decrease of the end surface 1a proceeds almost uniformly over the entire surface, so the amount of shrinkage of the end surface 1a during cooling becomes approximately constant over the entire surface, and the end surface 1a becomes a flat surface after cooling. .

[Effects of the Invention] As described above, the present invention includes a deburring ring inserted into the end of a plastic optical fiber, and a molding surface of a heated molding jig applied to the end surface of the optical fiber protruding from the deburring ring. In an end face finishing device that heat-forms the end face by pressing the end face until it abuts against a deburring ring, this device is equipped with a cooling means that cools the heat-formed part centered on the central part of the end face of the optical fiber. Since cooling is performed mainly in the central part of the end face where the cooling rate is slow, the temperature drop of the end face proceeds almost uniformly over the entire surface, and the amount of shrinkage during cooling of the end face is reduced over the entire surface. It becomes substantially constant, and there is an effect that the end surface after cooling does not become a concave curved surface unlike the conventional example, and the end surface can be easily finished into a flat surface.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the conventional example, Figure 2 is a detailed view of the main parts of the same as above, Figures 3 a and b are explanatory diagrams of the same as above, and Figure 4
The figure shows the heat shrinkage mechanism of a plastic optical fiber, Figure 5 is a cross-sectional view of an embodiment of the present invention, Figure 6 is a top view of the same essential parts, and Figure 7 is a front view of the important parts of the same. be. 1 is an optical fiber, 1a is an end face, 2 is a forming jig, and 15 is a cooling means.

Claims (1)

[Claims] 1. Insert a burring ring into the end of the plastic optical fiber, and press the molding surface of the heated molding jig against the end surface of the optical fiber protruding from the burring ring until it abuts against the burring ring. 1. An end face finishing apparatus for a plastic optical fiber, characterized in that the end face finishing apparatus for a plastic optical fiber is provided with a cooling means for cooling the heat formed part centered on the central part of the end face of the optical fiber.