IMAGE FIBER FOR OBSERVATION OF PIPING INSIDE

摘要

PURPOSE:To make the inside of a visual field bright and to enable the detailed observation by forming the exit end faces of optical guides diagonally with respect to the optical axis so that transmitted light is refracted by the exit end faces and can be effectively irradiated to the inside surface of a pipeline. CONSTITUTION:An image fiber 12 is inserted into a pipeline 11 and plural optical guides 13 are disposed around said fiber. The guides 13 are formed by fixing the exit ends of the bundled fibers bundled with many optical fiber strands with an adhesive agent and polishing the exit end face 13a thereof so as to incline toward the inside. Transmitted light is thus refracted to the outside by the face 13a in the stage of emitting therefrom and arrives effectively at the inside surface of the pipeline 11. The angle theta' of refraction depends on the angle theta of inclination of the face 13a like O'approx.=(n-1), where this equation holds when the theta is small and (n) is the refractive index of the core glass. Therefore if the theta' is changed by adjusting adequately the theta, the illuminating range A is made coincident with an observing range B and the dark part in the visual field is eliminated.