| 摘要 |
PURPOSE:To obtain a plastic light transmitting fiber superior in heat resistance and durability by forming a core of polycarbonate, a sheath of a transparent polymer specified in refractive index, and a protective layer of a polymer specified in heat deformation temp. CONSTITUTION:A light transmitting fiber is composed of a core 1 made of polycarbonate, a sheath 2 formed of a substantially transparent polymer having a refractive index >=0.01 lower than that of the core 1, and a protective layer 3 made of a polymer having a heat deformation temp. of >=110 deg.C. Light 4 incident at an incident angle theta3 is transmitted repeatedly totally reflected with the interlayer between the core 1 and the sheath 2, and light 5 incident at an incident angle theta4 is also transmitted repeatedly totally reflected with said interlayer, thus preventing noise. Further, light 6 incident from the outside of the protective layer 3 is totally reflected with the interlayer between the layer 3 and the sheath 2 and does not invade into the core 1, because the refractive index of the layer 3 is higher than that of the sheath 2, so no noise is detected. Hence, a plastic light transmitting fiber superior in light transmitting performance and heat resistance can be obtained. |
