OBJECTIVE LENS DEVICE, OPTICAL PICKUP DEVICE, OPTICAL-DISC DRIVING DEVICE AND DRIVING METHOD OF OBJECTIVE LENS

摘要

An objective lens device includes: a first objective lens having a first numerical aperture, which can condense light into a disc-shaped first optical recording medium including a first cover layer of first thickness; a second objective lens having a second numerical aperture which is smaller than the first numerical aperture, which can condense light into a disc-shaped second optical recording medium including a second cover layer of second thickness which is thicker than the first thickness; a third objective lens having a third numerical aperture which is smaller than the second numerical aperture, which can condense light into a disc-shaped third optical recording medium including a third cover layer of third thickness which is thicker than the second thickness; and a lens holder configured to integrally hold the first, second, and third objective lenses.