OPTICAL PICKUP AND INFORMATION DEVICE

摘要

An optical pickup (100) is provided with (i) a light source for outputting laser beams; (ii) an optical system (108 or the like) for guiding the outputted laser beams to one of a plurality of recording layers; (iii) a light receiving means (114) for receiving returning beams reflected by the recording layers; (iv) a pin hole (117) having a prescribed opening section which selectively transmits a part of one returning beam reflected by one recording layer, among the returning beams, so as to be received by the light receiving means; (v) a convertible lens (118 or the like) for changing a focal position so that the one returning beam is focused on a prescribed pin hole; (vi) a first control means (314) for controlling the convertible lens by applying a prescribed voltage so as to focus the one returning beam on the prescribed pin hole; and (vii) a calculating means (314c or the like) for calculating RF signals based on the one received returning beam.