| 摘要 |
A security Device comprises a zero order diffractive microstructure (5) buried within a substrate (3). One or more further optical structures, such as microlenses (1), may be formed on a surface (2) of the substrate (3). The further optical structures modify the optical characteristics of the zero order diffractive microstructure (5). Various alternatives or additional optical structures and methods of producing them are described in additional embodiments. |
