Method of forming an optically variable security device

摘要

A method of forming a security device comprises: a) providing an undeveloped photoresist layer on an electrically conductive layer; b) forming a first diffractive pattern in the undeveloped photoresist layer using optical-interferometry; c) forming a second diffractive pattern in the undeveloped photoresist layer using electron beam lithography; and d) thereafter developing the photoresist layer.