Magnetooptic recording member having selectively-reversed erasure directions in predetermined recording areas of the record member

Claim 1

A record member for storing information-bearing signals, the record member being divided into a plurality of addressable signal-storing areas and having a recording layer capable of recording said information-bearing signals along a plurality of elongated tracks with said addressable signal-storing areas being in said tracks, said layer respectively capable of assuming two sensible states, said sensible states representing first and second information bearing signals, respectively, and said first information bearing signal being an erased signal; the improvement including, in combination: each of said addressable signal-storing areas including a sensible mark signal recorded therein which indicates for that respective area the informational representation of each of said sensible states such that each addressable signal storing area can represent stored information differently by said sensible states, respectively, such that in first predetermined ones of said addressable signal-storing areas a first one of the sensible states represents said first information bearing signal and in second predetermined ones of said addressable signal-storing areas a second one of the sensible states represents said first information bearing signal whereby an erasure direction of the addressable signal-storing areas is determined by said sensible mark signals, respectively; and wherein said information-bearing signals include a plurality of different length half wavelength signals, including a signal having longer half wavelength than other ones of said information-bearing signals, said sensible mark signal includes a signal pattern having a signal with half wavelength equal to and having a length along said tracks in which is resides said longer half wavelength of the information-bearing signals recorded on said record member.