Patent ID: 7474598
Filing Date: 2009-01-06
Classification: G11B

Abstract:
1. An optical reproducing device comprising: predetermined length mark signal measurement means for measuring reproduction signal characteristics respectively of a short reproducing power control mark and of a long reproducing power control mark from information data that are recorded in a data recording area of a sector of an optical recording medium; and power control means for controlling reproducing power of a light beam based on the measured reproduction signal characteristics of the short and long reproducing power control marks, wherein the predetermined length mark signal measurement means further includes a pattern detection means for detecting a specific pattern including therein an arrangement of a plurality of short reproducing power control marks from amongst a bit arrangement pattern of the information data in the data recording area, and when the specific pattern is detected, to measure the reproduction signal characteristic of short reproducing power control marks, the measured reproduction signal characteristic of short reproducing power control marks corresponding only to the plurality of short reproducing power control marks included in the specific pattern.