OPTICAL SECURITY COMPONENT WITH REFLECTIVE EFFECT, PRODUCTION OF SUCH A COMPONENT AND SECURE DOCUMENT PROVIDED WITH SUCH A COMPONENT

摘要

According to one aspect, the invention relates to an optical security component intended for being observed under direct reflection. The component comprises a structure engraved on a layer of a material having a refraction index n2, a thin layer of a dielectric material having a refraction index n1 other than n2, deposited on the structure, and a layer of a material having a refraction index n0 other than n1, encapsulating the coated structure of the thin layer. The structure has a first pattern modulated by a second pattern such that, in at least one first region (61, 86), the first pattern comprises a low-relief with a first set of facets, the shapes of which are determined such as to generate at least one first concave or convex cylindrical reflective element, and the second pattern forms a first subwavelength grating acting, after depositing the thin layer and encapsulating the structure, as a first wavelength-subtractive filter; in at least one second region (62, 86), the first pattern comprises a low-relief with a second set of facets in which the shapes are determined such as to generate at least one concave or convex cylindrical reflective element (64), and the second pattern forms a second subwavelength grating acting, after depositing the thin layer and encapsulating the structure, as a second wavelength-subtractive filter, separate from the first wave-length-subtractive filter. Each subwavelength grating can be a zero order diffraction grating such as a DID.

主权项

1. An optical security component intended to be observed according to an observation face in a spectral band lying between 380 and 780 nm and in direct reflection, comprising:
a structure (S) engraved on a layer of a material exhibiting a refractive index n2, a thin layer of a dielectric material exhibiting a refractive index n1 different from n2, deposited on the structure; a layer of a material of refractive index n0 different from n1, encapsulating the structure overlaid with the thin layer, the structure exhibiting a first pattern modulated by a second pattern in such a way that: in at least one first region, the first pattern comprises a bas-relief with a first set of facets whose shapes are determined so as to generate at least one first cylindrical reflective element concave or convex seen from the observation face, exhibiting a first principal direction, and the second pattern forms a first sub wavelength grating acting, after deposition of the thin layer and encapsulation of the structure, as a first wavelength-subtractive filter; in at least one second region, the first pattern comprises a bas-relief with a second set of facets whose shapes are determined so as to generate at least one second cylindrical reflective element concave or convex seen from the observation face, exhibiting a second principal direction, and the second pattern forms a second sub wavelength grating acting, after deposition of the thin layer and encapsulation of the structure, as a second wavelength-subtractive filter, different from the first wavelength-subtractive filter.