| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an objective lens of an optical pickup which has small astigmatic variations when the temperature is distributed in a manner rotation asymmetric around the optical axis in an objective lens comprising at least two optical elements, and can make stable information recording/reproducing at high speed on a high-density optical disk, and also provide an optical pickup using this objective lens and an optical information recording and reproducing device using this optical pickup. <P>SOLUTION: The objective lens of the optical pickup is built with at least two optical elements, a 1st optical element disposed at the light source side and a 2nd optical element having a light condensing property disposed at the optical information recording medium side. The objective lens satisfies formula (1): D×τ<6.0, where τ[mm] represents the distance on the optical axis between the optical surface at the light source side of the above 1st optical element and the optical surface at the optical information recording medium side, and D [mm] represents the outer diameter of the 1st optical element. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
