| 摘要 |
A security document form such as a bank draft, or other document of value may incorporate a see-through and writeable hologram or diffractive grating as an anti-counterfeit measure. The hologram may extend over all or a portion of the form such as the signature entry area and other data entry areas of the form, e.g. the date, name and numerical value areas. A Previous patent utilizing metallized holograms for such applications does not permit good photocopying or microfilming of the document on account of their high reflectance. This photocopying problem is solved by using a see-through, writeable hologram which allows clearly legible photocopies to be made for legitimate use but appearing clearly fraudulent when passed off as the original. An ink-compatible top surface is made by coating with ink-receptive material or by corona discharge treatment as is well known in the industry. Writing or impact printing over the ink-compatible surface of the hologram partially occults the hologram underneath such writing and may cause the embossed surface of the hologram to become etched, so that even if the ink is somehow erased or removed, the writing trace would still remain, thus making it unalterable. The use of such an overlaminated hologram or diffractive grating can be accomplished by tamper-proof pressure sensitive holographic labeling, by hot-stamping the hologram with heat activated adhesive backing, or by embossing the hologram onto polymeric thermoplastic directly coated on the substrate paper or plastic card. The use of such a writeable hologram also permits incorporation of many other anticounterfeit features. Optionally, the hologram may also be covered with a protective laminate after the writing has been applied. This invention thus offer an aesthetically pleasing and cost effective means of forgery prevention for large volume users, while making it prohibitively costly for those attempting to counterfeit. |
