Patent Number: 6,807,018

Title: Objective lens for optical pick-up

Abstract: An objective lens of an optical pick-up is formed to provide axial astigmatism corresponding to wavefront aberration of 0.01.lambda. [rms] or more when a shorter wavelength laser beam emitted by a first laser diode is converged on a first optical disc, and to provide coma so that its sign when the shorter wavelength laser beam is converged on the first optical disc will be opposite to its sign when a longer wavelength laser beam emitted by a second laser diode is converged on a second optical disc.

Inventors: Maruyama; Koichi (Tokyo, JP), Yamanouchi; Takashi (Tokyo, JP)

Assignee: PENTAX Corporation

International Classification: G11B 7/125 (20060101); G11B 7/135 (20060101); G11B 7/00 (20060101); G02B 003/02 (); G02B 013/18 (); G11B 007/00 (); G11B 007/135 ()

Expiration Date: 10/12016