METHOD FOR OPTICAL DISK RECORDING AND REPRODUCING, OPTICAL DISK DEVICE, AND OPTICAL PICKUP

• Main Authors: FUJITA SHINJI, ISSHIKI FUMIO, MAEDA NOBUYUKI
• Format: Patent
• Language: English
• Published: 31.03.2005
• Edition: 7
• Subjects: INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; PHYSICS

PROBLEM TO BE SOLVED: To accurately and stably compensate a spherical aberration for an unrecorded write-once disk, and to detect a spherical aberration error signal with simple part composition in real time. SOLUTION: For an unrecorded write-once disk 20, a tracking servo is made inoperative, a push-pull signal is detected by a push-pull signal generating circuit 34 from outputs of a photo detector 12, in an in-focus state and an out-of-focus state, and a spherical aberration error signal A is obtained by a spherical aberration error detecting circuit 31 by calculating a difference in amplitudes between these push-pull signals. After compensating the spherical aberration with the signal A, a specific pattern signal is recorded in an area for trial writing and is reproduced in the in-focus and out-of-focus states. An amplitude of the reproduced signal for each state is obtained by a reproduced signal generating circuit 32, and a spherical aberration error signal B is obtained by the spherical aberration error detecting circuit 31 by calculating a difference between these amplitudes. The spherical aberration is compensated with the signal B. COPYRIGHT: (C)2005,JPO&NCIPI