JPH0159982B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing an infrared image guide used in fields such as measurement and medicine.

(Prior art) Conventionally, a glass rod made of chalcogenide glass or fluoride glass, such as arsenic sulfide or germanium sulfide, is inserted into a synthetic resin tube and drawn under heating to form a synthetic material around the glass core. An infrared image guide is manufactured by producing an infrared fiber having a cladding made of a resin tube, and then bonding a plurality of infrared fibers with their ends aligned in alignment.

(Problems to be Solved by the Invention) However, it is extremely difficult to tightly insert a glass rod into a synthetic resin tube, which inevitably creates a gap between the two. This has the disadvantage that this occurs in the infrared fiber, leading to a decrease in the strength and optical characteristics of the infrared fiber.

Furthermore, the strength of the drawn infrared fiber itself is very low, and the cladding is easily damaged, making it difficult to handle when making bundles of the infrared fiber. It is extremely difficult to align the phase accurately, and as the number of infrared fibers increases, the diameter of the core decreases, or the length of the infrared image guide becomes longer, it becomes difficult to align the phase accurately. It is no exaggeration to say that the current situation is that only short bundles with a small number of bundles and large core diameters can be manufactured.

The present invention aims to eliminate such drawbacks, and even if the infrared image guide has a large number of cores or a small core diameter, or even if it is long. The object of the present invention is to provide a simple and easy manufacturing method with good handling conditions.

(Means for Solving the Problems) A method for manufacturing an infrared image guide according to the present invention to achieve the above object is to heat a first heat-shrinkable synthetic resin tube with a glass rod inserted therein under reduced pressure. Then, a preform is prepared in which the first synthetic resin tube is brought into close contact with the surface of the glass rod, and this preform or a plurality of fibers drawn from the preform are inserted into a heat-shrinkable second synthetic resin tube. By heating the second synthetic resin tube to produce a bundle preform in which the plurality of preforms or fibers are bundled by heat contraction of the second synthetic resin tube, and drawing this bundle preform under heating. The present invention is characterized in that an infrared image guide is manufactured by using the first and second synthetic resin tubes as a cladding and having a plurality of glass cores inside the cladding.

(Example) Hereinafter, the method for manufacturing an infrared image guide according to the present invention will be explained based on the drawings. As shown in FIG. It is inserted into a first heat-shrinkable synthetic resin tube 2 such as resin (TFE) or tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP), and this is inserted into a vacuum container 4 to which a vacuum pump 3 or the like is connected. Interior decoration.

Then, a heater 5 is placed in the vacuum container 4 under reduced pressure.
The first synthetic resin tube 2 containing the glass rod 1 is heat-shrinked under reduced pressure by heating, and as shown in FIG. Create.

For example, if the diameter of the glass rod 1 is large, or if it is necessary to obtain a core with an extremely small diameter, the preform A is drawn under heating as shown in FIG. As shown in FIG. 4, a fiber Aa is prepared in which the glass rod 1 is the core 1a and the synthetic resin tube 2 is the clad 2a.

Below, we will continue to explain the method for manufacturing an infrared image guide using the fiber Aa.

Now, as shown in FIG. 5, a desired number of the fibers Aa are inserted into a heat-shrinkable second synthetic resin tube 6.
the second synthetic resin tube 6 is heated by the heater 7, and then the second synthetic resin tube 6 is heated.
By thermally shrinking the synthetic resin tube 6, a bundle preform B in which the desired number of fibers Aa is bundled is produced as shown in FIG.

Next, as shown in FIG. 7, while heating the bundle preform B with the heater 8, the bundle preform B is drawn from one end thereof, so that as shown in FIG.
The first and second synthetic resin tubes 2 and 6 are used as a cladding a, and a plurality of glass cores b are placed inside the cladding a.
An infrared image guide C having the following characteristics is manufactured.

Since the first synthetic resin tube 2 is heat-shrinked under reduced pressure, the adhesion between the first synthetic resin tube 2 and the glass rod 1 is extremely high, and the generation of bubbles can be prevented.

When drawing the bundle preform B, the first and second synthetic resin tubes 2 soften and fill the gap between the preforms A. can prevent bubbles from forming.

Note that the heating wire drawing of the preform A may be performed as necessary, as described above. For example, if the glass rod 1 is long and small in diameter, the heating wire drawing may be omitted. It is possible to implement it.

(Effects of the Invention) As explained above, the present invention bundles a plurality of preforms in which a first synthetic resin tube is brought into close contact with the surface of a glass rod, or a plurality of fibers obtained by drawing the preforms. Infrared image guides are manufactured by drawing wires, and workability is good because it handles large objects, and it is extremely easy to align the array positions of both ends accurately. Therefore, even if the infrared image guide has a large number of cores, has a small core diameter, or is long, it can be easily manufactured.

When producing the preform, the first synthetic resin tube into which the glass rod is inserted is heat-shrinked under reduced pressure, so that the degree of adhesion of the first synthetic resin tube to the surface of the glass rod is increased, and when drawing the bundle preform, , the first and second synthetic resin tubes soften and fill the gaps between the glass rods and glass cores, making it possible to manufacture an infrared image guide with strong mechanical strength and no air bubbles within the cladding. As a result, by a simple improvement of the method, the drawbacks of the conventional method could be successfully overcome.

[Brief explanation of drawings]

The drawings show one step of the method for manufacturing an infrared image guide according to the present invention, and FIG. 1 is a cross-sectional view showing a preform manufacturing state, FIG. 2 is a cross-sectional view of the preform, and FIG. 3 is a heating wire drawing state for fiber manufacturing. FIG. 4 is a cross-sectional view of the fiber corresponding to the - line cross-section in FIG. 3, FIG. 5 is a cross-sectional view showing how the bundle preform is manufactured, and FIG. be. Fig. 7 is a sectional view showing the drawing state, and Fig. 8 is a - of Fig. 7.
FIG. 3 is a cross-sectional view of the infrared image guide corresponding to a line cross section. DESCRIPTION OF SYMBOLS 1... Glass rod, 2... First synthetic resin tube, 6... Second synthetic resin tube, A... Preform, Aa... Fiber, B... Bundle preform, a... Clad, b... Glass core .

Claims (1)

[Claims] 1 Heat the first heat-shrinkable synthetic resin tube with the glass rod inserted inside it under reduced pressure,
A preform is prepared in which the first synthetic resin tube is brought into close contact with the surface of the glass rod, and this preform or a plurality of fibers drawn from the preform are inserted into a heat-shrinkable second synthetic resin tube, and the second synthetic resin tube is inserted into the second synthetic resin tube. By heating the resin tube and thermally shrinking the second synthetic resin tube, a bundle preform in which the plurality of preforms or fibers are bundled is produced, and this bundle preform is drawn under heating. A method for manufacturing an infrared image guide, comprising manufacturing an infrared image guide having a plurality of glass cores inside the first and second synthetic resin tubes as a cladding.