Memorias de investigación
Artículos en revistas:
Security devices based on liquid crystals doped with a colour dye
Año:2011
Áreas de investigación
  • Tecnología electrónica y de las comunicaciones
Datos
Descripción
Liquid crystal properties make them useful for the development of security devices in applications of authentication and detection of fakes. Induced orientation of liquid crystal molecules and birefringence are the two main properties used in security devices. Employing liquid crystal and dichroic colorants, we have developed devices that show, with the aid of a polarizer, multi? ple images on each side of the device. Rubbed polyimide is used as alignment layer on each substrate of the LC cell. By rub? bing the polyimide in different directions in each substrate it is possible to create any kind of symbols, drawings or motifs with a greyscale; the more complex the created device is, the more difficult is to fake it. To identify the motifs it is necessary to use polarized light. Depending on whether the polarizer is located in front of the LC cell or behind it, different motifs from one or the other substrate are shown. The effect arises from the dopant colour dye added to the liquid crystal, the induced orientation and the twist structure. In practice, a grazing reflection on a dielectric surface is polarized enough to see the effect. Any LC flat panel display can obviously be used as backlight as well.
Internacional
Si
JCR del ISI
Si
Título de la revista
OPTO?ELECTRONICS REVIEW
ISSN
1896-3757
Factor de impacto JCR
1,027
Información de impacto
Volumen
19
DOI
Número de revista
4
Desde la página
92
Hasta la página
96
Mes
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Participantes
Grupos de investigación, Departamentos, Centros e Institutos de I+D+i relacionados
  • Creador: Grupo de Investigación: Grupo de Fotónica Aplicada
  • Centro o Instituto I+D+i: Centro de Materiales y Dispositivos Avanzados para Tecnologías de Información y Comunicaciones
  • Departamento: Tecnología Fotónica y Bioingeniería