| CPC G02B 5/287 (2013.01) [B42D 25/324 (2014.10); B42D 25/351 (2014.10); B42D 25/364 (2014.10); B42D 25/373 (2014.10); B42D 25/425 (2014.10); B42D 25/45 (2014.10); B42D 25/475 (2014.10); B42D 25/29 (2014.10); B42D 25/355 (2014.10)] | 15 Claims |
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1. A method of producing a semi-finished product with at least one liquid crystal security feature, comprising:
unrolling and transporting a continuous film in a transporting direction; and
providing on the continuous film a liquid crystal layer containing at least one substance whose absorption of polarized light depends on its orientation;
prior to providing the liquid crystal layer, arranging a lacquer layer on the continuous film,
embossing the lacquer layer to provide a first alignment structure,
at least partly covering the embossed lacquer layer with the liquid crystal layer, wherein the first alignment structure is arranged to cause liquid crystal molecules of the liquid crystal layer to align in different directions in different ones of a plurality of regions of the liquid crystal layer, the plurality of regions comprising:
one or more first regions in which the liquid crystal molecules align only in a first direction;
one or more second regions in which the liquid crystal molecules align only in a second direction, which is essentially orthogonal to the first direction; and
one or more third regions including one or more first areas in which the liquid crystal molecules are aligned only in the first direction and one or more second areas in which the liquid crystal molecules are aligned only in the second direction;
wherein each of the plurality of regions forms a pixel of an image in which, when viewed with linearly polarized light, the one or more first regions are perceptible with a change in contrast with respect to the one or more second regions, and the one or more third regions are perceptible in a halftone relative to the one or more first regions and the one or more second regions; and
wherein the first direction is arranged to deviate from the transporting direction by an angle of between 20° and 70°, an angle of between 30° and 60°, or an angle of 45;
wherein embossing the lacquer layer to provide the first alignment structure is such that at least two of the one or more third regions have a different area ratio of the one or more first areas with the liquid crystal molecules aligned in the first direction relative to the one or more second areas with the liquid crystal molecules aligned in the second direction; and
wherein the at least two of the one or more third regions are perceptible in different halftone tones relative to the one or more first regions and the one or more second regions.
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