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

摘要

An objective lens device, an optical pickup device, an optical disc driving apparatus and a driving method of the objective lens are provided to make an objective lens device thinner by allowing the device to accept three formats of recording media. An objective lens device comprises a first objective which condenses light to a first optical recording medium of disc shape having a first cover layer of a first thickness and has a first numerical aperture; a second objective lens which condenses light to a second optical recording medium of disc shape having a second cover layer of a second thickness greater than the first thickness has a second numerical aperture smaller than the first numerical aperture; a third objective lens which condenses light to a third optical recording medium of disc shape having a third cover layer of a third thickness greater than the second thickness and has a third numerical aperture less than the second numerical aperture; and a lens holder(26) for holding the first, the second and the third lens together.