Polygram International Holding B.v.

U.S. Philips Corporation

Hans Schuddekopf

Hermann Koop

Karsten Benne

In a method of marking optically readable disc-shaped information carriers which are manufactured, for example, by a transfer-moulding process using at least one mould serving as a stamper, which mould has been derived from a master via at least two electroforming replication steps, the mould is provided with a marking for the subsequent indentification of the mould, which marking is situated in an otherwise information-free area of the information carrier to be manufactured and allows the mould thus marked to be identified.

Method of marking disc-shaped information carriers

The invention relates to disc-shaped information carriers which can be read optically in reflection and which contain an annular information zone which is bounded by a concentric inner zone and a concentric outer zone. The information carrier consists of a transparent substrate and has a readout side and opposite side (back) which at least in the information zone has a reflective coating. The light entering the outer zone from the readout side is reflected at least partially diffusely or absorbed by the information carrier. In this way, manufacturing defects such as, for example, inclusions, inhomogeneities etc. are at least partially masked or concealed.

Disc-shaped information carrier and method of manufacturing it

The invention relates to disc-shaped information carriers which can be read optically in reflection and which contain an annular information zone which is bounded by a concentric inner zone and a concentric outer zone. The information carrier consists of a transparent substrate and has a readout side and an opposite side (back) which at least in the information zone has a reflective coating. The light entering the outer zone from the readout side is reflected at least partially diffusely or absorbed by the information carrier. In this way, manufacturing defects such as, for example, inclusions, inhomogeneities etc. are at least partially masked or concealed.

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Hanover, Germany

Hans Schuddekopf