Patent ID: 8125865
Filing Date: 2012-02-28
Classification: G11B

Abstract:
1. An optical disc comprising first and second information recording layers on which user data is recorded, the user data being recorded and reproduced through a same light incidence side of the optical disc on the first and second information recording layers, wherein the first information recording layer comprises a first test area located at an inner radius, a second test area located at an outer radius, and a first data recording area configured to record the user data, the second information recording layer comprises a third test area located at an inner radius, a fourth test area located at an outer radius, and a second data recording area configured to record the user data, and wherein the first test area and the third test area are located at different radiuses and do not overlap each other, the second test area and the fourth test area are located at substantially equal radiuses, and the second information recording layer does not have any other test area that is located so as to overlap with the first test area of the first information recording layer.