Patent ID: 7929394

Claim:
An optical record carrier comprising a first information plane having an information structure which is optimally read in a first read mode and at least a second information plane having an information structure which is optimally read in a second read mode; each of said information planes storing information which is readable by a read device which scans the record carrier from one side thereof, which read device includes: (i) an optical system for focusing a radiation beam on a selected one of said information planes which is to be read; (ii) a detection system for receiving radiation from the record carrier resulting from the radiation beam and producing a detection signal based on the received radiation, which detection signal includes a read signal resulting from the information plane being read and one or more interference signals resulting from other of said information planes; and (iii) a read circuit for deriving from the read signal an information signal corresponding to the information stored in the information plane being read, said read circuit having an interference ratio Q associated therewith which is indicative of an operational characteristic thereof; the information planes being spaced at a distance from each other and having optical properties such that the ratio of the sum of said interference signals to the read signal is smaller than said interference ratio Q.