Hot embossing of micrographic elements in polypropylene
Micrographic features generated by electron beam lithography have been hot embossed in biaxially-oriented polypropylene (BOPP). Each micrographic element consisted of a sub-field of 3030?m with a specific configuration of symbols, lettering and graphics. The micrographic elements were integrated with arrays of diffractive gratings in the form of an optically variable device. A high quality embossing of various micrographic elements has been demonstrated in features with a linewidth dimension ?365nm and depth ?255nm. The replication of arrays of micrographic elements was achieved uniformly over an area of 2020mm in the BOPP film by embossing at a temperature of 130C.
hot embossing micrographic bopp