| 摘要 |
A device for examining an object, preferably a document of value, by using optical radiation, having an optical waveguide which has an anisotropic retro-reflector section, which is formed along a surface curved in a plane of curvature and which reflects radiation components specularly in a first plane of incidence parallel to the plane of curvature but retro-reflects radiation components orthogonally with respect to the first plane of incidence, so that at least a proportion of the optical radiation falling in a glancing manner on the retro-reflector section is at least partly guided on the convex side of the surface by reflection on the retro-reflector section. |
