Optical pickup apparatus for simultaneously reading data from a plurality of tracks of an optical disc

Abstract

An optical pickup apparatus () for reading data from a plurality of tracks of an optical disc () at the same time by focussing spots (M, . . . ) of each light beam on a plurality of tracks, passing the reflected light beams of spots (M, . . . ) sequentially through an objective lens (), a collimator lens (), and a focus adjusting lens () in this order, and detecting the reflected light beams with photodiodes (M, . . . ) disposed along a photodiode light reception plane (). In order to make each reflected light become incident upon each photodiode (M, . . . ), a case () and a bracket () are separated from a chassis (), and support the focus adjusting lens () and the photodiodes (M, . . . ) respectively. The case () and bracket () are made so that they can be fixed to the chassis () at optional positions in a predetermined area along a direction of the optical axis (). While the case () and bracket () are moved along the optical axis () direction, positions along the optical axis () where the reflected light beams are allowed to enter the photodiodes (M, . . . ) are searched and the case () and bracket () are fixed to the chassis () at the searched positions.