| 摘要 |
A security document comprises a substrate (1) and an optical waveguide (7). Couplers (10a, 10b) are provided in the waveguide (7) for coupling light into and out of the waveguide. The couplers (10a, 10b) can e.g. by gratings, scattering objects, holograms, luminescent dyes or perforations. The authenticity of the document can be verified using methods based on the properties of the waveguide. The security document is characterized by further comprising a periodic microlens-array (15), wherein said coupler (10a, 10b) has a periodic structure, with the microlens-array having a period substantially equal to said periodic structure. |
