U.S. Philips Corporation

Rinse Dijkstra

Gerardus J Lippits

Arnoldus J Van Den Broek

Adriaan J Op Het Veld

Jelis De Jonge

Wilhelmus Sprangers

The invention relates to a method of reproducing plastics record carriers, in particular duplicating video records. According to the invention, a metal die is used which is provided with a thin-liquid molding resin of a particular composition which can be polymerized by radiation. A radiation-pervious substrate which is manufactured from synthetic material, for example polymethylmethacrylate, is provided on the molding resin. The molding resin is exposed to light via the substrate after which the cured molding resin together with the substrate connected thereto is removed from the die. The molding resin used in the process comprises low-molecular monomers or oligomers which contain on an average 25-70% by weight of hydrocarbon groups and/or phenyl groups. The molding resin is aprotic and has a functionality as regards unsaturatedness which is between the values 2 and 6. A suitable molding resin contains mono-, tri- or tetra esters of acrylic acid. The molding resin preferably has a swelling capacity with respect to the substrate and for that purpose preferably comprises a vinylmonomer. The metal die used in the method preferably is a quite flat die which is obtained by providing the master disk which is a flat glass plate with information track with a nickel layer, gluing hereon a flat stiffening plate and then removing the master disk. The resulting father disk may be used as a die. Alternatively, further metal copies may be made herefrom which are provided in a simpler manner with a flat stiffening plate. The invention also extends to the molding resin, substrate and die used in the method, as well as the resulting plastics record carriers.

Method of manufacturing a die for duplicating plastics information

Bake out is accelerated and made possible at a lower temperature when at least one metal organic compound defined by the general formula

Method of producing mouldings and layers of inorganic materials

The invention relates to a method of reproducing plastics record carriers, in particular duplicating video records. According to the invention, a metal die is used which is provided with a thin-liquid molding resin of a particular composition which can be polymerized by radiation. A radiation-pervious substrate which is manufactured from synthetic material, for example polymethylmethacrylate, is provided on the molding resin. The molding resin is exposed to light via the substrate after which the cured molding resin together with the substrate connected thereto is removed from the die. The molding resin used in the process comprises low-molecular monomers or oligomers which contain on an average 25-70% by weight of hydrocarbon groups and/or phenyl groups. The molding resin is aprotic and has a functionality as regards unsaturatedness which is between the values 2 and 6. A suitable molding resin contains mono-, tri- or tetra esters of acylic acid. The molding resin preferably has a swelling capacity with respect to the substrate and for that purpose preferably comprises a vinylmonomer. The metal die used in the method preferably is a quite flat die which is obtained by providing the master disk which is a flat glass plate with information track with a nickel layer, gluing hereon a flat stiffening plate and then removing the master disk. The resulting father disk may be used as a die. Alternatively, further metal copies may be made herefrom which are provided in a simpler manner with a flat stiffening plate. The invention also extends to the molding resin, substrate and die used in the method, as well as to the resulting plastics record carriers.

Method of duplicating plastics information carriers

The invention relates to an information disc having a laminated structure which can be read optically. The information disc comprises a transparent substrate which is preferably manufactured from a synthetic resin, for example plexiglass, having thereon a radiation-cured lacquer layer in which the information track is present. The lacquer layer used comprises a radiation-cross linkable protic compound which after curing is aprotic. The lacquer layer preferably comprises a polythiol compound as well as a polyene compound in an equivalent ratio of 1:1.

Optically readable information disc

The invention relates to a disk-shaped record carrier, for example a video plate, which is provided on one side or on both sides with a radiation-reflecting surface structure in the form of an information track consisting of blocks and pits on which a reflecting layer of metal is provided. The plate can be read optically. According to the invention the reflecting metal layer is provided with a cover layer which is formed by a transparent plate which is connected to the metal surface by means of a radiation-curable lacquer. The lacquer is preferably a U.V. curing lacquer and contains a protic mixture of acrylic acid esters. The transparent plate is also preferably manufactured from a transparent synthetic resin and has a thickness of 200 .mu.m.

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Eindhoven, Netherlands

Rinse Dijkstra