DEVICE AND METHOD FOR REPRODUCING OPTICAL DISK

摘要

PROBLEM TO BE SOLVED: To record sub-information without increasing the cost required for manufacturing a disk and degrading the reading accuracy of main information, and to reproduce the sub-information by reliable and stable reading.SOLUTION: An optical disk reproducing device includes: a predetermined area-specifying circuit which specifies a position of a predetermined area, where a postscript mark is recorded at least in a part; a pit and/or land length-detecting circuit which detects each length of a plurality of pits and/or lands contained in a predetermined area; and a predetermined length-discriminating circuit which discriminates that each detected pit and/or land length is equal to or more than the predetermined length. The center part of a pit and/or a land which are discriminated to be equal to or more than the predetermined length is taken as a detecting section of second information and the second information is reproduced from a reproduction signal of the second information detection section.