| 摘要 |
PURPOSE:To obtain a polycrystalline fiber for infrared rays which has less transmission loss of light and large mechanical strength, by melting a ground mixture of a polycrystalline material and specific single crystal or glass, and making into a fiber by extrusion. CONSTITUTION:Materials 7 obtained by grinding a base material of a polycrystalline material and on additive into powder are mixed and then supplied into a high frequency heating furnace 5. While high pressure is applied by a pressure piston 6, the materials are heated at a high frequency to be molten. In this case, the temperature is higher than the melting point of the additive and lower than that of the base material. This molten material is applied with pressure by the pressure piston 6 to be extruded from the tip 8 of the high frequency heating furnace 5 in the form of a fiber, which is wound around a take-up reel 11. As said additive, single crystal or glass is used which has a refractive index, a coefficient of thermal expansion, and an infrared-ray transmitting range nearly equal to those of the polycrystalline material, and also has a lower melting point than point than said polycrystalline material and physical isotropy. |
