| 摘要 |
A document includes a substrate which has an outer surface and defines a plane, and a coordinate system which is defined with respect to the plane. A diffraction-optical authenticating element covers at least part of the outer surface, and generates at least one color pattern constituting a visually testable feature which verifies the authenticity of the document. The diffraction-optical authenticating element provides a color pattern moving at a predetermined velocity along a predetermined track when the document is illuminated from a first direction and viewed from a second direction, as defined with respect to the coordinate system, upon the document being rotated within the plane along a prearranged sense of rotation, and at a prearranged velocity. |
