| 摘要 |
PROBLEM TO BE SOLVED: To provide a fiber having an optical and designing effect, which effectively receives sunlight and artificial light from a side face of the fiber, and can efficiently transmit the incident light to a bent part, an uneven part and a cut end face part.SOLUTION: The core-sheath type composite fiber has a core part that mainly comprises a polymer containing a fluorescent substance and a sheath part that mainly comprises a transparent polymer, on the other hand. A relationship between a refractive index nof the core part and a refractive index nof the sheath part satisfies n-n≥0.02. |
