| 摘要 |
<p>A security card blank comprises a plurality of superposed layers (5,5',6,7,8,9) including a metallic layer (5,5'). The metallic layer comprises any radiation absorbent, metal, metalloid, or their alloys or derivatives, such as oxides or sulphides. The metallic layer (5,5') is positioned within the card blank and is imageable only under the influence of high intensity radiation to produce a security card. After imaging, at least part of the imaged metallic layer is detectable from outside the card. </p> |
