Document type
Patents
Title
Holographic credit card - capable of being read by infrared radiation through a transparent film
Participants in the publication
J. M. Rebordão (Author)
INSTITUTO NACIONAL DE ENGENHARIA, TECNOLOGIA E INOVAÇÃO
J. C. Freitas (Author)
INSTITUTO NACIONAL DE ENGENHARIA, TECNOLOGIA E INOVAÇÃO
Summary
The card consists of a film (1) contg. a substance which absorbs visible light but is transparent to infra-red, a plastics transparent film (2) coated on its upper face by a layer (3) of reflective ink, which is followed by a layer (4) of protective ink. Validity of the cards is checked by an electro-optical deVice (5), capable of gradually destroying the credit vailable. Use of holographic techniques allows engraving in a suitable substrate of a micro-relief protected by a foil only transparent in the infra-red region. This micro-relief deflects by diffraction the light emitted by an infra-red source (6) in a certain direction different from that of mirror reflection. It is produced by embossing with rigorous control of technical, mechanical and ambient conditions. PT19840079271
Date of Submisson/Request
1984-09-26
Data de Concessão
1986
Institution
INSTITUTO NACIONAL DE ENGENHARIA, TECNOLOGIA E INOVAÇÃO
Publication Identifiers