| 摘要 |
PURPOSE:To irradiate an optical fiber which is coupled at one end to a light source linearly with uniform brightness by forming flaws reaching the core thereof to said fiber and making the density thereof nonuniform. CONSTITUTION:An optical fiber 2 is coupled at one end to a light source 1. Many flaws 4 reaching the core from the surface thereof are formed to the fiber 2, and the density of the flaws 3 is made nonuniform in the extension direction of the fiber 2. Since the photoelectric power injected into the fiber 2 from one end decreases toward the other end, the density of the flaws 4 is increased toward the other end of the fiber 2 conversely from the attenuation tendency of the photoelectric power. More specifically, if the density of the flaw is defined as (n), the position in the extension direction of the optical fiber as gamma, the position for starting illumination of the optical fiber as gammao, and a constant as C, the flaws are formed in the respective positions of the optical fiber at the density expressed by n=1/ce<-(gamma-gammao> . |
