OPTICAL DISC AND OPTICAL DISC RECORDING PLAYBACK APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide an optical disc which does not suffer the leak-in that the polarizing direction of a reflected light at grooves is affected by wobbles to thereby give influence on playback characteristics and is capable of surely generating synchronizing signals. SOLUTION: An optical magnetic disc 540 has grooves and lands, the grooves are structured such that grooves 551 have each a wobble 553 provided at either wall thereof and are followed at the back by zones where grooves 554 having no wobble and grooves 555 having no bobble at both sides are alternately disposed. As the result, the lands are structured such that lands 552 have wobbles 553 each provided at either wall thereof and is followed at the back by zones having no wobble.