Patent ID: 8369201
Filing Date: 2013-02-05
Classification: G11B

Abstract:
1. An optical pickup comprising: an optical system comprising: an object lens to illuminate a first light for performing information recording or information reproducing on a recording layer as a target and a second light different from the first light with respect to an optical recording medium, which includes a reference plane having a reflection film and the recording layer which is disposed at a layer position different from that of the reference plane and on which information recording is performed through mark formation according to light illumination; a focus-aligned position adjusting unit to adjust a focus-aligned position of the first light through the object lens by changing collimation of the first light incident to the object lens; and a focusing mechanism to drive the object lens in a focusing direction, which is a direction of approaching/separating with respect to the optical recording medium, wherein a depth of focus λ/NA