Substrate with a modified liquid crystal polymer marking
AssigneeSicpa Holding SA
InventorsThomas Tiller, Olivier Rozumek, Tristan Jauzein, Andrea Callegari, Frédéric Gremaud, Brahim Kerkar
Life of this patent
Estimating the term…
Abstract
The present invention relates to a marking on an item or substrate, which marking is based on a chiral nematic (also called cholesteric) liquid crystal precursor composition. Prior to curing the chiral liquid crystal precursor composition in the chiral liquid crystal state at least one optical property exhibited by the composition is modified by two modifying agents of different types in at least one area of the item or substrate.
Claims33
A marking on an item or substrate, wherein the marking comprises a layer or pattern of a chiral liquid crystal polymer composition that exhibits an initial set of optical properties and is made by curing a chiral liquid crystal precursor composition in a chiral liquid crystal state and wherein the layer or pattern comprises
- (1) one or more first areas exhibiting a first modified set of optical properties that is different from the initial set of optical properties and is obtainable by contacting the chiral liquid crystal precursor composition in the one or more first areas with a first modifying agent;
- (2) one or more second areas exhibiting a second modified set of optical properties that is different from the initial set of optical properties and different from the first modified set of optical properties and is obtainable by contacting the chiral liquid crystal precursor composition in the one or more second areas with a second modifying agent that is of a different type than the first modifying agent.
A method of providing a marking on an item or substrate, wherein the method comprises:
- a) applying onto a surface of an item or substrate which carries a first modifying agent in one or more first areas a curable chiral liquid crystal precursor composition which has an initial chiral liquid crystal state upon heating it in such a way that the composition covers at least a part of the one or more first areas, the first modifying agent being able to modify an initial chiral liquid crystal state of the composition;
- b) heating the applied composition to bring the same to a first modified chiral liquid crystal state in the one or more first areas and to the initial chiral liquid crystal state in all other areas, if any, of the applied composition;
- c) applying to one or more second areas of the applied composition at least one second modifying agent which is of a different type than the first modifying agent and (1) is able to locally modify the initial and/or first modified chiral liquid crystal states provided by b), or (2) is able to locally modify the initial and/or first chiral liquid crystal states provided by b) upon heating the composition;
- d) in the case of (2), heating the composition at least in the one or more second areas;
- and
- e) curing the thus modified chiral liquid crystal precursor composition to produce a chiral liquid crystal polymer marking on the item or substrate.
Dependencies are inferred from the claim text.