| 摘要 |
PURPOSE:To make it possible to make an optical system such as a pickup thin by deflecting luminous flux which is cast into one aspherical surface from a reflecting surface, and emitting the luminous flux from another aspheric surface. CONSTITUTION:A deflection-type aspherical lens 21 has two convex protruding aspherical surfaces 22a and 22b and one reflecting surface 23. Luminous flux 24 which is cast into one aspherical surface 22a is deflected from the reflecting surface 23 by 90 deg. and converged through the other aspherical surface 22b. When the deflection-type aspherical lens 21 is constituted in this way, a riser mirror is not required when especially the lens is used as a pickup for recording and regenerating the data with respect to an optical recording medium. Therefore, the pickup can be made compact and thin. |
