HIGH DENSITY INFORMATION RECORDING MEDIUM, INFORMATION RECORDING AND REPRODUCING METHOD AND INFORMATION RECORDING AND REPRODUCING DEVICE TO BE USED FOR ITS EXECUTION

摘要

PURPOSE: To obtain recording capacity of not less than that of the CD-ROM of the size of 12cms by using the disk of not more than the size of about 2.5 inches. CONSTITUTION: This medium is a disk shaped high density information recording medium 1 recording and reproducing information with respect to information tracks by using an optical spot and a recording area 2 in which information tracks are formed has zones 3 and respective zones have sectors 4. Respective sectors have a pre-format information area and a data information area of ruggedness pits on information tracks and the combination between the number of sectors of respective zones and information track pitches are selected so as to be user capacity not less than 640MB. The radius of the disk 1 is about 32mm and the recording area 2 is provided in the part whose radius is from about 15mm to about 30mm. The information track pitches are 0.65μm to 0.85μm. There are information tracks constituted by including land parts and information tracks constituted by including groove parts in information tracks.