Abstract: A master disc for the manufacture of copies which in turn are used for the manufacture of further copies in the form of optically readable information carriers, the master disc comprising a substrate disc which is provided with an optical recording layer which comprises a nitrocellulose binder as well as a dye which is dissolved or finely dispersed in said binder, the dye being a squarylium dye which is used in a quantity of 1-15 wt. % of the binder.

Abstract: The invention relates to a method of manufacturing a metal matrix suitable for use in the manufacture of optical discs, in which a master plate is used which comprises a recording double layer of a synthetic resin in which each layer comprises a laser light-absorbing dye, the master plate is exposed to modulated laser light in which the laser light in both layers of the recording layer is absorbed and in which as a result of the exposure information bits are formed in the form of bumps having variable longitudinal dimensions and the same width dimensions and the master plate on the side of the recording layer comprises a metal layer which is separated from the master plate, as well as a master plate which is suitable for use in the method described hereinbefore.

Abstract: A master disc which is provided on one side with a reflective optical structure and a recording double-layer is exposed to a first laser beam which scans the optical structure and to a second laser beam which is controlled by the first beam, information bits in the form of bulges being formed in the recording layer due to exposure to the second beam, a metal skin being subsequently provided on the recording layer, in which metal skin the surface structure of the recording layer is copied and, finally, the matrix thus obtained being removed from the master disc.

Abstract: Method of recording information, recording element manufactured according to the method and method of producing a metal matrix.Recording in which a recording double layer which has an absorbing dye is exposed to laser light of a higher and a lower energy level, in which by exposure to laser light of the lower energy level, a bump is formed in the recording layer and in which by exposure to laser light of the higher energy level a bulge is formed which at the surface comprises a groove, as well as a recording element obtained by using the method and a method of manufacturing a metal copy from the recording element.

Abstract: A master disc which is provided on one side with a reflective optical structure and a recording double-layer is exposed to a first laser beam which scans the optical structure and to a second laser beam which is controlled by the first beam, information bits in the form of bulges being formed in the recording layer due to exposure to the second beam, a metal skin being subsequently provided on the recording layer, in which metal skin the surface structure of the recording layer is copied and, finally, the matrix thus obtained being removed from the master disc.

Abstract: The master disc contains a substrate plate which is preferably provided with an optically detectable guide track and a recording layer of polysulphone such as poly(1-butene sulphone) to which, preferably, a colorant is added and in which an optically readable information track is provided by patterned exposure, a pit or groove being formed in the polysulphone layer. A matrix is formed by applying a metal layer to the polysulphone layer by means of an electroless deposition process and then, applying a further metal layer by means of an electrodeposition process or applying a curable synthetic resin layer together with a metal disc, after which the synthetic resin is made to cure.

Abstract: Recording in which a recording double layer which has an absorbing dye is exposed to laser light of a higher and a lower energy level, in which by exposure to laser light of the lower energy level, a bump is formed in the recording layer and in which by exposure to laser light of the higher energy level a bulge is formed which at the surface comprises a groove, as well as a recording element obtained by using the method and a method of manufacturing a metal copy from the recording element.