摘要 |
PURPOSE:To widen an irradiation area greatly by forming spiral flaws, which extend from the surface of an optical fiber to the core, in the cladding layer, and emitting light from a light source linearly in the elongation direction of the optical fiber. CONSTITUTION:In the figure, 1 is a light source and 2 is an optical fiber, which consists of a core 21 constituting a center part and a cladding layer 22 covering the core surface. Then, 4 is numbers of spiral flaws formed in the cladding layer and they are deep enough to reach the core 21. Each beam travels straight while repeatedly reflected in the core 21 to reach some flaw 41 in the interface between the core 21 and cladding layer 22, and is then emitted out of the optical fiber as light beam, 5 through said flaw. Because of the spiral shape of the flaws 4, when the optical fiber is viewed on the whole, light having nearly the same intensity is emitted from each part of the flaw, thus performing light irradiation which is seen as if it were nearly linear in the elongation direction of the optical fiber. |