| 摘要 |
PURPOSE:To obtain efficient illumination from near observation to far observation by forming the projecting end part of optical guide fiber flux like a circular arc, turning the projecting end surface upward and forming a plane section including the end surface upward the center of the circular arc. CONSTITUTION:Individual fibers 7c forming optical guide fiber flux 7 are turned to the tangential direction of the circular arc around a center at the projection part 7b. The plane section 9 including the projecting end surface 7a is not passed through the center 8 and arranged upward, so that the direction of the fibers 7c on the end surface 7a are successively changed and the most inner fiber 7a is expanded from the most outer fiber 7j upward by an angle A. At the projection of irradiating light from the end surface, the light rays are refracted, so that the angle formed by the optical axes P, Q of the fibers 7i, 7j is expanded up to an angle B. If it is defined that the light distribution angle of each fiber flux is C and the light distribution angle of the plane section including the observing optical flux 2a of the fiber flux 7 and the illuminating optical flux 3a is D, D=C+B and the light distribution of illuminating light projected from the fiber flux 7 is expanded by the angle B on the plane section including both the optical axes.
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