| 摘要 |
PURPOSE:To obtain an optical fiber having a protecting film which protects the fiber against blackening by visible rays and ultraviolet rays by passing the fiber consisting of silver halide in an eutectic mixture contg. silver sulfide and depositing silver sulfide on the fiber surface. CONSTITUTION:A fiber 1 consisting of silver halide produced by a puller 3 is guided to guide rollers 4, 5, and is introduced into the inlet part 6a of a melt tank 6. The melt 7 of an Ag2S-AgCl type eutectic mixture contg. sulfide is contained in the tank 6, and the temp. in the tank 6 is so set as to be successively lower from an inlet part 6a toward an outlet part 6b. In the inlet part 6a, the melt 7 of silver sulfide and silver chloride sticks on the surface of the fiber 1, and in the intermediate part 6c and in the outlet part 6b, only the silver sulfide deposits on the surface of the fiber 1. The melt of the silver chloride having stuck on the surface of the fiber 1 returns into the melt 6. In this way, the protecting film consisting of silver sulfide is formed on the surface of the fiber 1. |
