SECURITY DEVICE

摘要

A security device with multiple layers. A substrate provides the backing to a first luminescent layer. An optically variable structure is positioned between the first luminescent layer and a second luminescent layer. Both the first and second luminescent layers emit luminescent radiation when stimulated. When the first layer is stimulated, the optically variable structure filters the emitted luminescent radiation such that the emitted luminescent radiation only escapes the optically variable structure at a predetermined range of emission angles. A user, when viewing the security device from the predetermined range of angles as both layers are stimulated, can see a completed image of a predetermined indicia. When the security device is viewed at angles other than the predetermined range of angles as both layers are stimulated, a user will only see an incomplete image of the predetermined indicia.

主权项

1. A security device comprising:
a first luminescent layer which, when stimulated, emits luminescent radiation of at least a first wavelength; a second luminescent layer which, when stimulated, emits luminescent radiation of at least a second wavelength; an optically variable structure for controlling said luminescent radiation of said first luminescent layer, said structure being constructed and arranged to permit emission of luminescent radiation of said first wavelength through said structure at a first range of angles, said structure being constructed and arranged to minimize emission of luminescent radiation from said first luminescent layer for a second range of angles;wherein
said optically variable structure is positioned between said first luminescent layer and said second luminescent layer; said first luminescent layer is positioned such that said emission of luminescent radiation through said structure at said first range of angles is visible to a user; said second luminescent layer is positioned to allow said user to view emission of luminescent radiation of said second wavelength from said second luminescent layer at least one predetermined angle; said first luminescent layer, when producing luminescent radiation of said first wavelength, forms a first image; said second luminescent layer, when producing luminescent radiation of said second wavelength, forms a second image; said first image complements said second image such that when said first and second image are viewed together, said first and second image form a third image .