| 摘要 |
<p>PCT No. PCT/GB86/00109 Sec. 371 Date Oct. 30, 1986 Sec. 102(e) Date Oct. 30, 1986 PCT Filed Mar. 3, 1986 PCT Pub. No. WO86/05300 PCT Pub. Date Sep. 12, 1986.An identifiable security device comprises a carrier (1), such as a key card, credit card or document, supporting a thick film hologram (5) including at least one discrete reflective region (6) which, when illuminated reflects strongly in a specific, predetermined direction. A reader (2) incorporates a light source (7) and one or more photodiode detectors (8,11) arranged to detect the directional reflections, to discriminate against non-holographic reflections and to perform a security function on detection of appropriate reflections. The function may comprise authentication of a carrier bearing a simple hologram, but more complex hologram having a plurality of reflective regions arranged in a coded array are used, for example, on bank cheque cards to operate automatic bank dispensers and on pass cards for gaining entry to secure areas.</p> |
