| 摘要 |
PROBLEM TO BE SOLVED: To obtain a small, highly portable and large recording capacity optical disk by providing a specific diameter, thickness and track pitch, dividing a recording area into a plurality of zones in radial direction, and enabling recording information of more than specific amounts in a data compression state. SOLUTION: For improving portability, an optical disk is formed with a diameter smaller than 64 mm and a thickness thinner than 0.8 mm. The diameter is favorable near 50 mm in order to carry in a pocket the recording/reproducing device using this optical disk as recording media. The storage capacity is set larger than the 650 MB, favorably 1.0 GB or above so as to record an image information of 45 minutes (at 3.3 Mbps) or above in a data compression state. In order to increase the recording capacity while having a smaller diameter than that of MD, it is desirable to use a super-high resolution method reproducing a smaller recording pit than the light beam spot size. |
