| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a cylindrical lens 10 moldable with surface smoothness more excellent than conventional one. Ž<P>SOLUTION: This cylindrical lens 10 has a step difference pattern of multistage elliptic cone shape where a plurality of elliptic truncated cones with sizes different each other is multistagedly piled up concentrically along an optical axis direction, as the step difference pattern for light diffraction. In the cylindrical lens 10, stages other than the center stage that is the stage positioned in the most central side in the step difference pattern are formed into a shape surrounding endlessly the center stage, extended along an orbit nearer to the elliptical center than an elliptical orbit in the major-axis-directional central area respectively in both major-axis-directional end areas, while curved along the elliptical orbit in the major-axis-directional central area, and consecutive to a curved portion in the central area. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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