Optical disc

摘要

In an optical disc recording-reproducing apparatus using a standard optical disc enclosed in a cartridge (1), an optical plate (19) for correcting various aberrations generated by a focusing lens (18) is comprised therein in order to allow use of a double recording optical disc enclosed in a standard cartridge of the same size; the optical plate (19) is placed in front of the focusing lens (18) when the double recording optical disc is used, and is removed from the front of the focusing lens (18) when the standard optical disc is used.