| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a high numerical aperture optical pickup lens which secures a longer working distance while maintaining its excellent characteristics on and outside its axis. <P>SOLUTION: The optical pickup lens 1a is a single lens to focus the light flux from the laser light source on an optical information recording medium. Out of its two surfaces, the shape of the R2 surface 12 opposite to the R1 surface 11 close to the laser light source has a continuous shape, and has radiuses h1, h2, h3 satisfying 0>Δsag1>Δsag2, and Δsag2<Δsag3, when representing radiuses by radius h1, radius h2, radius h3 (h1<h2<h3) from the optical axis to the outside, and the sags at radius h1, radius h2, radius h3 by sag1, sag2, sag 3, and their variations by Δsag1, Δsag2, Δsag3. <P>COPYRIGHT: (C)2008,JPO&INPIT |
