| 摘要 |
<p>Pre-paid cards such as telephone cards which have an intrinsic value yet are adapted to be disposable after validation of the card has occurred and the user thereof subsequently becomes entitled to the credit value of the card in respect of a particular service, such as a telephone service. The cards are printed with a number of layers including an opaque abradable or scratchable layer (38, 40) which is removed by the user to reveal the card indicia layer (32). The card uses a relatively light permeable plastic or paper substrate (10) and to prevent the indicia (32) from being fraudulently read by shining an intense light at the rear of the card, the layers embody a confusion pattern layer (36) disposed either under the abradable layer (38, 40) to be removed therewith or under the indicia and which registers with the indicia. The confusion pattern is ideally dependent on the particular indicia such that in combination, the indicia and the confusion pattern render deciphering of the indicia impossible.</p> |
