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US 4,477,328 AGranted
Optically readable information disk and method of manufacturing same
AssigneeU.S. Philips Corporation
InventorsEgbert Broeksema, Arnoldus A. Smeets
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AssigneeU.S. Philips Corporation
InventorsEgbert Broeksema, Arnoldus A. Smeets
Estimating the term…
The invention relates to an optically readable information disk, a method of manufacturing same, as well as a device for carrying out the method, in which the information disk which comprises an optically readable information track of information areas situated at a higher and a lower level, is manufactured entirely from a radiation-cured layer of a lacquer containing oligomeric acrylates or methacrylates which on an average per molecule comprise between one and four acrylate groups or methacrylate groups, has a viscosity of 1,000-15,000 cP and comprises a photoinitiator in a concentration of 0.1 to 0.5% by weight. Suitable lacquers comprise notably 1,1'-isopropylene-bis(p-phenoxyethylmethacrylate) or 1,1'-isopropylene-bis(p-phenoxyethylacrylate).
A self supported optically readable information disk of radiation cured synthetic resin having a thickness of about 0.5-3 mm the surface of which disk comprises an optically readable information track having a relief structure of information areas situated alternatively at a higher and lower level and which disk is formed by the irradiation of a radiation curable liquid composition having a viscosity of 1000-15,000 cP and comprising oligomeric acrylates or methacrylates which on the average per molecule comprise between one to four acrylate or methacrylate groups and a photoinitiator in a concentration of 0.1 to 0.5 percent by weight.
A method for manufacturing an optically readable information carrier, said information carrier being a self supported radiation cured synthetic resin disk, characterized in that a radiation-curable liquid composition which comprises oligomeric acrylates or methacrylates which on an average comprise per molecule between 1 and 4 acrylate groups or methacrylate groups, which liquid composition has a viscosity of 1,000-15,000 cP and comprises a photoinitiator in a concentration of 0.1 to 0.5% by weight, is introduced into a moulding cavity formed between two parallel arranged matrices, at least one of the two matrices on its surface facing the other matrix having an information track which has a relief structure of information areas situated alternately at a higher and a lower level, the introduced layer is then cured by radiation via one or both matrices and the resultant cured disk in which the information track has been copied is removed from the mold after opening the matrices and, if desired, is provided with a reflective layer on the side of the information track.
Dependencies are inferred from the claim text.