| 摘要 |
<p>An authentication card or tag (1) comprises a laminate (2, 3, 4) which bears a hologram (5) viewable at an obverse thereof and whose reverse is provided by a light-transmitting ply (4) of the laminate which overlies artwork viewable through that ply. The reverse comprises a figured light-refracting surface (6) of that ply or a light diffracting layer thereof whereby the perceived image of said artwork alters according to the angle at which it is viewed.</p> |
