OPTICAL DATA STORAGE

摘要

Optical data storage members are disclosed in which the <> present between data-carrying tracks of conventional data storage members are used to carry information recorded in a manner which avoids the danger of cross-talk between adjcent tracks. One preferred arrangement consists of an optical data storage member comprising an optically-recordable surface having a plurality of tracks in which information may be recorded in analogue or digital form, the tracks being of a first type in which the material constituting the track is sensitive to radiation of a first predetermined characteristic and a second type in which the material thereof is sensitive to radiation of a second predetermined characteristic, wherein tracks of the first type alternate across the surface of the optical data storage member with tracks of the second type. The tracks may be constituted by a surface region carrying a plurality of closely spaced grooves, the grooves of one track being orthogonally directed with respect to those of its adjacent tracks. The predetermined radiation characteristic can be the polarisation state of the incident radiation.