Patent ID: 6285646
Filing Date: 2001-09-04
Classification: G11B

Abstract:
An objective lens to selectively focus light emitted from a laser source onto a first optical recording medium and a second optical recording medium having different thicknesses, the objective lens comprising:a first lens area having an aspherical surface to focus light emitted by the laser source onto the first optical recording medium and the second optical recording medium;a second lens area having an aspherical surface to focus light emitted by the laser source onto the second optical recording medium; anda third lens area having an aspherical surface to focus light emitted by the laser source onto the first optical recording medium, whereinsaid first lens area reduces optical aberration with respect to the first optical recording medium and the second optical recording medium,said second lens area reduces optical aberration with respect to the second optical recording medium, andsaid third lens area reduces optical aberration with respect to the first optical recording medium.