| 摘要 |
PURPOSE: To detect the radial skew by using an optical recording medium forming first and second patterns ranging to plural tracks so as to make reflection light quantities characteristics opposite to each other. CONSTITUTION: When no radial skew exists (radial skew=0), since laser spots 5 are a real circular shape though the laser spots 5 scanning on a present scan track 3B come to both positions of pit patterns A, B, laser beams converge only pits 4B1 .4B2 on the track 3B. Since a signal level RA and the signal level RB of information read in respective positions by the pit patterns A, B are equal to each other, when a difference between both of the signal level RA and the signal level RB is defined a detection level RDS, RDS=0 (RDS≡RA-RB=0), and the absence of the radial skew is detected. |
