| 摘要 |
An authentication apparatus operative to determine the authenticity of an item comprising a film substrate responsive to detection that a portion of said item located in a measuring region of said apparatus has a predetermined birefringence characteristic, said apparatus comprising: an item detection arrangement operative to determine if at least a portion of an item is located in a measuring region of said authentication apparatus; and an optically-based birefringence measuring apparatus, wherein said authentication apparatus is operative to compare a measured birefringence characteristic with a predetermined birefringence characteristic and to produce an authenticity signal indicative of authenticity or otherwise of said item based upon said comparison, said apparatus further comprising a control means operative to control output of said authenticity signal from said apparatus responsive to determination, by said item detection arrangement, of presence or otherwise of said at least a portion of said item in said measuring region. |
