The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 23, 1981
Filed:
Nov. 16, 1979
Gerardus J Lippits, Eindhoven, NL;
Arnoldus J Van Den Broek, Eindhoven, NL;
Adriaan J Op Het Veld, Eindhoven, NL;
Rinse Dijkstra, Eindhoven, NL;
Jelis De Jonge, Eindhoven, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
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.