| 摘要 |
PURPOSE:To provide the low transmission loss optical fiber and the multifilament type optical fiber having decreased picture element defects by removing the foreign matter and more particularly gelatinous foreign matter included in a resin raw material constituting the light transmission body by a specific filter. CONSTITUTION:The resin raw material in a molten state constituting the light transmission body is filtered by the filter of the type formed by superposing long metallic fibers in small diameter to a non-woven fabric form and sintering these fibers and is then supplied to a spinning nozzle, by which the resin raw material is spun and the light transmission body is formed. Namely, a spinning mouthpiece constituted of a mouthpiece 1 for forming a core, a mouthpiece 2 for forming a sheath, a mouthpiece 3 for forming a sea component, a core component distributing plate 4, a core component supplying port 5, a sheath component supplying port 6, a sea component supplying port 7, an aggregating mouthpiece 8 and a multifilament type optical fiber discharging port 9 are used. Polymethyl methacrylate is used as the sheath component and a polyfluooromethacrylate polymer as the sea component. After only the resin for forming the core component is filtered by using the filter of the non-woven fabric type of the long stainless steel fibers as the filter, the resins are subjected to composite spinning. |
