Patent PH-12013000336-A1 (PH)
Title: Method for verifying the authenticity of a document or product on which an optical component is arranged
Inventor: SOUPARIS HUGUES
IPC: B42D25/00
Filed: 2013-10-31
Abstract: The present application concerns a method for verifying the authenticity of a document or product on which an optical security component is arranged. The optical security component comprises a transparent layer of refractive index n0 comprising a first area having a zero-order diffractive structure having a grating vector oriented in a direction, a second area having the zero-order diffractive structure having a grating vector oriented in a direction perpendicular to the direction of the grating vector of the zero-order diffractive structure of the first area, and a third area having a first-order diffractive structure. The component further comprises a layer of refractive index n1 different from n0 at least partially coating the first and second areas, and a layer of refractive index n2 similar to n0 coating the layer of refractive index n1. The component is configured to produce, for a first orientation of the component, a colored effect of a first color in the first area and a colored effect of a second color in the second area, and to produce, for a second orientation of the component perpendicular to the first orientation by an azimuthal rotation of the component, the colored effect of the second color in the first area and the colored effect of the first color in the second area. The method comprises a) illuminating the component with natural light, b) positioning the document or productd so as to observe, with a naked eye, a first-order diffraction in the third area, c) from the position of step b), tilting from top to bottom the document of product so as to observe, with a naked eye, the colored effect of the first color in the first area and the colored effect of the second color in the second area, and d) from the position of step c), verifying, with a naked eye, a color permutation of the colored effect in the and second areas by an azimuthal rotation of about 90 degrees of the document or product. The method further comprises e) illuminating the optical security component with a linearly polarized light, f) positioning the document or product so a to observe the colored effect of the first color in the first area and a colored effect extinction in the second area, and g) from the position of step f), verifying an extinction of the colored effect of the first color in the first area and either an appearance of the colored effect of the first color in the second area by an azimuthal rotation of about 90 degrees of the document or product or an appearance of the colored effect of the second color in the second area by a rotation of about 90 degrees of the polarization direction of the light. Alternately, the method further comprises e) illuminating the optical security component with natural light, f) positioning the document or product so a to observe, through a polarizer, the colored effect of the first color in the first area and a colored effect extinction in the second area, and g) from the position of step f), verifying, through a polarizer, an extinction of the colored effect of the first color in the second area by an azimuthal rotation of about 90 degrees of the document or product or an appearance of the colored effect of the second color in the second area by a rotation of about 90 degrees of the polarization direction of the light.