Patent ID: 6351440
Filing Date: 2002-02-26
Classification: G11B

Abstract:
A disc reproducer for rotating a disc, comprising:a detector detecting a condition reflecting an imbalance in a radial direction of said disc and outputting an imbalance signal; and a rotator for rotating said disc in accordance with a result of said detecting, wherein said rotator is more specifically capable of rotating said disc at a normal speed and at least one substitute speed, said at least one substitute speed being different than said normal speed; and said rotator operating at said at least one substitute speed when said imbalance signal is indicative of a rotational irregularity condition of said disc, wherein said detector is more specifically a dynamic detector detecting said condition reflecting an imbalance while said disc is rotated, wherein said rotator is more specifically capable of rotating said disc at a plurality of different substitute speeds, and stepping rotating of said disc through said plurality of different substitute speeds starting from a low substitute speed and progressing toward a high substitute speed; said detector detecting for occurrence of a radial imbalance while said disc is operated at each speed of at least a subset of said plurality of substitute speeds; and said rotator, when radial imbalance does occur, limiting rotating to a highest substitute speed at which radial imbalance does not occur.