| 摘要 |
A multi-layered sheet giving a forgery prevention effect by developing different appearances when the upper surface or lower surface is irradiated with an ultraviolet ray. In a first embodiment, fluorescence colouring layers respectively developing different hues are provided on the upper surface side and the lower surface side respectively, a fluorescence colouring layer on the upper surface side only develops a fluorescence colour to permit observation from the upper surface when an ultraviolet ray is applied from the upper surface side, and at least a fluorescence colouring layer on the lower surface side develops a colour to permit observation from the upper surface when an ultraviolet ray is applied from the lower surface side. In a second embodiment an opacity in an area extending from the upper surface to a fluorescence colouring layer is not lower than 97% and that in an area extending from the lower surface to a fluorescence colouring layer is not higher than 96%, and an ultraviolet radiation from the upper surface does not permit a printed pattern to be observed, whereas an ultraviolet radiation from the lower surface permits the printed pattern to be observed. |
