| 摘要 |
PURPOSE:To improve storage capacity by properly using one of two shapes of an elliptic and an egg-shaped pits and recording data with ternary code. CONSTITUTION:An optical disk 1 is driven at a constant high speed, and by a read/write head 3, a laser beam LB is converged to a spot and imparted, and the reflected beam is detected at a reading time, and is made a read signal RS through an amplifier 5. For enlarging the shape difference of an elliptic shape pit P1 form an egg-shaped pit P2, a heat insulation effect is increased by making a ZnS film in an A1 film side rather shick. Although the pit P1 written by a first recording level L1 becomes the elliptic shape, the pit P2 by a level L2 becomes the egg-shape. In such a manner, by using the ternary code as a recording code, the storage capacity is more increased than the case when a binary code is used. |
