Indentification of articles using liquid crystal identity cards

• US 4,536,014 A
• Filed: 08/24/1982
• Issued: 08/20/1985
• Est. Priority Date: 01/08/1981
• Status: Expired due to Fees

• Current Assignee: Securicard Systems Limited 12 Hope Street Edinburgh
• Original Assignee: Securicard Systems Limited
• Inventors: Kerekess, Tibor T., Boutaleb, Aboubekr, Boutaleb, Lucy A.
• Primary Examiner(s): Corbin, John K.
• Assistant Examiner(s): Lewis, David
• Application Number:
  US06/414,535
• Time in Patent Office: 1,092 Days
• Field of Search: 350/331 R, 350/334, 350/341, 283/72, 283/83, 283/86, 283/89, 283/87, 283/904, 283/901, 428/1, 353/65, 353/122, 356/71
• US Class Current: 283/83
• CPC Class Codes: B42D 25/00 Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof printing processes to produce identification or security features B41M3/14
• CPC Class Codes: B42D 25/23 Identity cards
• CPC Class Codes: B42D 25/309 Photographs
• CPC Class Codes: B42D 25/318 Signatures
• CPC Class Codes: B42D 25/351 Translucent or partly translucent parts, e.g. windows
• CPC Class Codes: B42D 25/364 Liquid crystals
• CPC Class Codes: B42D 25/45 Associating two or more layers
• CPC Class Codes: B42D 25/47 using adhesives
• CPC Class Codes: G02F 1/1313 specially adapted for a particular application
• CPC Class Codes: G06K 19/14 the marking being sensed by radiation
• CPC Class Codes: G07C 9/253 visually
• CPC Class Codes: G07F 7/086 by passive credit-cards adapted therefor, e.g. constructive particularities to avoid counterfeiting, e.g. by inclusion of a physical or chemical security-layer for security documents G07D7/00; for the reading of record-carriers in general G06K7/00; for the design of coded credit-cards G06K19/10

Abstract

An identification article, especially an identity document, has a marked element (8), e.g. a photograph covered by a mask (2) which is normally opaque but which, upon application of a suitable electric field changes to an at least translucent state. Preferably the mask (2) complies a liquid crystal layer (16) sandwiched between two plates (5 and 7) of which one plate is at least translucent.

Claims

1. An identity system comprising a plurality of flat laminated identity cards and a viewer therefor, each said identity card comprising an element bearing markings and a mask permanently overlying said markings and opaque so as to block said markings from view, the mask being of a material which, upon the application of a suitable electric field, changes from the opaque state to an energized state whereby the said markings can be viewed, and said viewer comprising a spaced pair of plate electrodes, means for supporting any of said identity cards between said electrodes, and means for applying an electrical field to the electrodes to energize the mask of said card to change from its opaque to its energized state, one at least of said electrodes being in the energized state whereby the revealed markings in the identity card can be viewed through said electrode.

2. An identity system as claimed in claim 1, wherein the mask comprises a liquid-crystal layer.

3. An identity system as claimed in claim 2, wherein the mask comprises a liquid-crystal layer sandwiched between a pair of polarizing plates.

4. An identity system as claimed in claim 3, wherein the liquid-crystal substance is a nematic liquid crystal substance and the plates have parallel grooves on their respective inner surfaces, the grooves in one plate being perpendicular to those in the other plate whereby the liquid crystal substance forms a twisted nematic layer.

5. An identity system as claimed in claim 3, wherein the liquid-crystal substance is a cholesteric liquid-crystal substance.

6. An identity system as claimed in claim 2, wherein the mask comprises a dye-containing liquid-crystal layer sandwiched between a pair of at least translucent plates.