| 摘要 |
PURPOSE:To reduce variation in the optical level during rotation by forming ring-shaped optical paths symmetrical about an axis of rotation through optical systems for convergence and deflection, and converging light beams from plural light sources on photodetectors corresponding to the light sources. CONSTITUTION:Light emitted by a light source O1 reaches the condenser lens LC1 directly through hollow parts of wedgelike prisms WP1 and WQ1 to become parallel luminous flux, which is converged by a condenser lens LC2 as a standstill body and then converged on a point O2 on the axis through hollow parts of wedgelike prisms WP2 and WQ2. Light from the other light source P0 becomes hollow conic luminous flux through a luminous flux conversion optical system VP and passes through a point P1 in a plane perpendicular to an axis of rotation running on O1 and its optical path is bent by the wedgelike prism WP1 to obtain ring-shaped parallel luminous flux through the condenser lens LC1. Then, the light is converged through the condenser lens LC2 as a standstill body and converted by the other luminous flux conversion system VP, from hollow luminous flux to solid conic luminous flux, which is converged on P0'. Further, light from a light source Q0 is converged on Q0'. |
