EIN DIFFRAKTIVES SICHERHEITSELEMENT

摘要

The diffractive optical device (1) can be used as a security device in the fields of authentication, identification and security. It comprises a zero-order diffractive color filter (3). The diffractive color filter may consist of a microstructured high-index layer (32) embedded between two low-index layers (31, 33). A mirror layer (4) for reflecting towards the diffractive color filter (3) at least part of light transmitted through the diffractive color filter (3) are provided beneath the diffractive color filter. Thanks to the mirror layer (4), the device (1) has a much higher reflected intensity and much more complex spectra than prior-art diffractive color filters.