Decorative substrate, especially costume jewelry gem with color effect and method for achieving color effect in the decorative transparent substrate

摘要

In the present invention, there is disclosed a decorative substrate, especially costume jewelry gem with color effect being characterized in that it consists of a transparent substrate containing on the backside in the following order from the backside 2 to 80 nm thick optically modifying layer formed by at least one element or an element oxide being selected from the group consisting of Ge, Si and Ti, Zr, Nb and Al oxides, which can be optionally doped with other elements, a reflecting layer formed by at least one metal or a metal alloy being selected from the group consisting of Au, Ag, Cu, Al, Cr, Ti, aluminium bronzes and alloys of Au, Ag and Cu and having thickness ensuring maximum possible reflection of impinging visible light in dependence on spectral reflectance of material from which the reflecting layer is made, back into the transparent substrate, 10 to 100 nm thick intermediate layer formed by at least one metal being selected from the group consisting of Ti, Cr and Cu, and a layer of protective varnish. An adhesive layer being 2 to 15 nm thick and formed by at least one metal oxide being selected from the group of metals consisting of Al, Ti, Zr a Sn can be optionally disposed between the optically modifying layer and the reflecting layer. There is also disclosed a method for achieving color effect in the decorative transparent substrate, said method comprising application of the above-indicated layers to the backside of a transparent substrate by vacuum sputtering and optionally heat treatment of the transparent substrate at a temperature exceeding 150 degC but being lower than the temperature at which deterioration of any indicated layer or undesired interaction of the layers can take place, for a period of 0.5 to 8 hours.