| 摘要 |
PURPOSE:To grasp characteristics of sensitivity, an optimum recording condition, etc. of a disk medium without using an exclusive measuring device, by recording a reference signal in a part of an optical disk which is capable of recording and reproducing. CONSTITUTION:In a track guide groove 1 which is formed spirally or concentrically on a disk, an information pit 3 is recorded by a pit pattern whose inter- pit distance is varied like d1-dn. Each pit group P1-Pn is separated by a sufficient distance, and a special mark 2 is inserted as a synchronizing signal in case of read and evaluation. From a characteristic obtained by preparing such a reference pattern by changing the pit size, the resolving power can be evaluated. Also, by controlling consciously the control of automatic focusing, the relation of a resolving power characteristic, an automatic focusing characteristic and a read light spot can be evaluated separately. |
