| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup lens having both satisfactory on-axis characteristics and off-axis ones, and capable of ensuring a longer working distance in a high NA optical pickup lens. <P>SOLUTION: The optical pickup lens has a first surface where luminous flux from a laser light source enters, and a second one at a side opposite to the first surface and facing an optical disk. The optical pickup lens is a single lens, where a numerical aperture NA for condensing the luminous flux from the laser light source of which wavelength is not more than 410 nm exclusively to the optical disk is not less than 0.84, an effective diameter D is 1.8≤D≤2.45 mm, and a center thickness d is 1.1≤d≤1.68495 mm. The surface shape of the second surface is continuous and is such that the center section projects and there are no recesses at the circumferential fringe so that inclination (Δsag) changes from gentle to sharp and becomes gentle again to reach the outer-periphery edge at the outer-periphery edge toward the outside from a lens center h0 agreeing with a light axis. <P>COPYRIGHT: (C)2010,JPO&INPIT |
