| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an objective lens for an optical disk having a numerical aperture of ≥0.75, superior in on-axis aberration, off-axis aberration and eccentric aberration between surfaces and constituted of a bi-aspherical single lens. <P>SOLUTION: The objective lens is the bi-aspherical single lens having a numerical aperture of ≥0.75, and an angle formed by a normal line N to the 1st surface 1 and an optical axis at the highest incident point of light L0 is controlled to be equal to or smaller than one of 55°, 56° and 57°. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
