| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup lens which reliably has a longer working distance while achieving satisfactory on-axis characteristics and off-axis characteristics, in a high-NA optical pickup lens. <P>SOLUTION: The optical pickup lens 1a is a single lens which focuses a beam of light from a laser light source onto an optical information recording medium. Of two surfaces of the optical pick up lens 1a, an R2 surface 12 on the opposite side from an R1 surface 11 closer to the laser light source has a continuous surface shape. There exist a radius h1, a radius h2, and a radius h3 (h1<h2<h3) extending from the light axis toward the outer edge of the lens, which satisfy 0>Δsag1>Δsag2 and Δsag2<Δsag3, where sag1, sag2, and sag3 are the amounts of sags at the radii h1, h2, and h3, and the variations of the sags are Δsag1, Δsag2, and Δsag3, respectively. <P>COPYRIGHT: (C)2010,JPO&INPIT |
