OPTICAL LENS AND OPTICAL PICKUP AND OPTICAL DISK USING THEREOF

摘要

PURPOSE: An optical lens and optical pickup and optical disk using thereof is provided to exclude a light beam of external of an optical effective face. CONSTITUTION: The optical lens constituted a transparency material. A face of source of light is a convex-type non-spherical face of revolution symmetry. The non-spherical face is formed spherical face without a stepped cone to radius direction. In a predetermined radius position, a differential coefficient of the function has a portion of discontinuity. A ray of light incident to inside of the predetermined radius position is focused on a predetermined position of the lens. A ray of light incident to outside of the predetermined radius position is not focused.