Abstract: An optical element where a first and a second image is at least partially encoded by a pattern of a non-periodic, anisotropic surface relief microstructure such that when light is incident on the surface of the element the first image is optimally visible under a first viewing angle and the second image is optimally visible under a second viewing angle. The optical element is particularly useful for securing documents and articles against counterfeiting and falsification.

Abstract: An optical element where a first and a second image is at least partially encoded by a pattern of a non-periodic, anisotropic surface relief microstructure such that when light is incident on the surface of the element the first image is optimally visible under a first viewing angle and the second image is optimally visible under a second viewing angle. The optical element is particularly useful for securing documents and articles against counterfeiting and falsification.

Abstract: The invention relates to an optical device comprising two patterned retarders and a reflective polarizer between the retarders. Information which is stored in the pattern of the retarders can be observed both in transmission and reflection. The device according to the invention can be used as high security element, for example for banknotes.

Abstract: The invention relates to an optical security device with multiple hidden images which become visible by arranging a polarizer above or below the device. Additional images become visible upon rotation of the polarizer. The optical device comprises two patterned optical retarders and a polarizer between the retarders.

Abstract: The invention relates to an optical security device with multiple hidden images which become visible by arranging a polarizer above or below the device. Additional images become visible upon rotation of the polarizer. The optical device comprises two patterned optical retarders and a polarizer between the retarders.

Abstract: The present invention relates to an optical element wherein a first and a second image is at least partially encoded by a pattern of a non-periodic, anisotropic surface relief microstructure such that when light is incident on the surface of the element the first image is optimally visible under a first viewing angle and the second image is optimally visible under a second viewing angle. The elements according to the invention are particularly useful for securing documents and articles against counterfeiting and falsification.

Abstract: The invention relates to an optical device comprising two patterned retarders and a reflective polarizer between the retarders. Information which is stored in the pattern of the retarders can be observed both in transmission and reflection. The device according to the invention can be used as high security element, for example for banknotes.

Abstract: The present invention relates to a method for the replication of a patterned surface relief microstructure, comprising the steps of generation of a first layer with a patterned surface relief microstructure, generation of a master, by copying the microstructure of the first layer into a second layer, thereby involving at least one dry or wet etching step, characterized by an additional step, in which the microstructure of the master is brought into contact with a replica material, such that the microstructure of the master is reproduced in the replica. The invention further relates to the elements made as a replica according to the method. The surface relief microstructures are suitable to display images with a positive-negative and/or color image flip. The elements according to the invention are particularly useful for securing documents and articles against counterfeiting and falsification.

Abstract: The present invention relates to a method for the replication of a patterned surface relief microstructure, comprising the steps of generation of a first layer with a patterned surface relief microstructure, generation of a master, by copying the microstructure of the first layer into a second layer, thereby involving at least one dry or wet etching step, characterized by an additional step, in which the microstructure of the master is brought into contact with a replica material, such that the microstructure of the master is reproduced in the replica. The invention further relates to the elements made as a replica according to the method. The surface relief microstructures are suitable to display images with a positive-negative and/or color image flip. The elements according to the invention are particularly useful for securing documents and articles against counterfeiting and falsification.