| 摘要 |
PURPOSE: To enable a user to use an optical information recording medium without being conscious of a difference in standards and to make it possible to reduce the cost of a recording and reproducing device. CONSTITUTION: This optical information recording medium is based on at least the two standards varying in substrate thickness including the first standard of the substrate thickness ta and the second standard of the substrate thickness tb(ta<tb). The recording medium has a first information recording part 3a corresponding to the first standard formed in the position of the distance ta from a luminous flux incident surface 1-1 and a second information recording part 3b corresponding to the second standard formed in the position of the distance tb from a luminous flux incident surface 1-1. |
