Optical disc having plural zones of constant density

Recording device comprising:

• a recording head;
• and
• recording control means for recording data at a substantially constant density on an optical disc including a recording area with circular or spiral tracks, which recording area is subdivided in a plurality of coaxial annular zones, the tracks having periodic characteristics which are radially aligned within each one of the zones, the periodicity being indicative of a track density for the track concerned, the average of the track densities within one zone being substantially equal to the constant density, the recording control means are arranged for detecting the periodic characteristics and for recording depending on the detected characteristics, a same predetermined amount of data in each track within one of the zones at the track density.

A read device comprising:

• a reading head;
• and
• read control means, for reading data from an optical disc recorded at a substantially constant density, the optical disc including a recording area with circular or spiral tracks, which recording area is subdivided in a plurality of coaxial annular zones, the tracks include periodic characteristics which are radially aligned within each one of the zones, the periodicity being indicative of a track density for the track concerned, the average of the track densities within one zone being substantially equal to the constant density, the read control means are arranged for detecting the periodic characteristics and for reading depending on the detected characteristics, a same predetermined amount data from each track within one of the zones at the track density.