A reflective film includes a first optical stack that provides a first reflective characteristic and a second optical stack that provides a second reflective characteristic. The optical stacks also have first and second absorptive characteristics that are suitable to absorptively heat the respective stacks upon exposure to light including a write wavelength while maintaining the structural integrity of the stacks. The absorptive heating can change the first and second reflective characteristics to third and fourth reflective characteristics, respectively. A blocking layer that at least partially blocks light of the write wavelength may also be provided between the optical stacks to permit absorptive heating of any selected one of the optical stacks. The reflective characteristics of the optical stacks can thus be independently modified in any desired patterns by appropriate delivery of light beams that include the write wavelength.

The invention relates to an optical security system comprising an optical element with a patterned anisotropic optical property, wherein information is encoded and encrypted in the pattern of the optical element. The system further comprises a patterned polarizer in which the pattern is such that the information stored in the optical element can be decrypted.

An anti-counterfeit medium, a method for manufacturing the same and a method for preventing counterfeiting are provided. The anti-counterfeit medium includes a retardation layer having birefringence and a reflection layer, and identification data is recorded in the anti-counterfeit medium. The identification data is divided into a plurality of partial images, and a plurality of transparent areas which correspond to the plurality of partial images are disposed adjacent to each other in the same plane so as to form the retardation layer, the plurality of transparent areas having optical axes which are oriented in different directions from each other in a rotation direction. The identification data includes biometric information.

An anti-counterfeit medium, a method for manufacturing the same and a method for preventing counterfeiting are provided. The anti-counterfeit medium includes a retardation layer having birefringence and a reflection layer, and identification data is recorded in the anti-counterfeit medium. The identification data is divided into a plurality of partial images, and a plurality of transparent areas which correspond to the plurality of partial images are disposed adjacent to each other in the same plane so as to form the retardation layer, the plurality of transparent areas having optical axes which are oriented in different directions from each other in a rotation direction. The identification data includes biometric information.

A diffusely reflective optical film includes a blended layer extending from a first to a second zone of the film. The blended layer includes first and second polymer materials separated into distinct first and second phases, respectively. The blended layer may have the same composition and thickness in the first and second zones, but different first and second diffusely reflective characteristics in the first and second zones, respectively. The difference between the first and second diffusely reflective characteristics may not be attributable to any difference in composition or thickness of the layer between the first and second zones. Instead, the difference between the first and second diffusely reflective characteristic may be attributable to a difference in birefringence of the first and/or second polymer materials between the first and second zones. The blend morphology of the blended layer may be substantially the same in the first and second zones.

A diffusely reflective optical film includes a blended layer extending from a first to a second zone of the film. The blended layer includes first and second polymer materials separated into distinct first and second phases, respectively. The blended layer may have the same composition and thickness in the first and second zones, but different first and second diffusely reflective characteristics in the first and second zones, respectively. The difference between the first and second diffusely reflective characteristics may not be attributable to any difference in composition or thickness of the layer between the first and second zones. Instead, the difference between the first and second diffusely reflective characteristic may be attributable to a difference in birefringence of the first and/or second polymer materials between the first and second zones. The blend morphology of the blended layer may be substantially the same in the first and second zones.

A security element for safeguarding of articles of value, has a motif layer based on a liquid-crystalline material intended and destined to form a latent motif. The security element includes a first embossing varnish layer disposed on a carrier film, a partial motif layer based on a nematic liquid-crystalline material, and a single- or multilayer second embossing varnish layer present over the full area. The first embossing varnish layer has been provided with an embossment having at least two regions with alignment structures of different orientation for formation of a second latent motif. The motif layer, in the form of a first latent motif, is disposed in regions directly atop the first embossing varnish layer and in an overlapping arrangement with the regions that form the second latent motif.

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.

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.

A security device is provided including a first pattern of elements and a second, overlapping, pattern of elements spaced by a transparent layer, the first and second patterns in combination obstructing the passage of light transmitted to a viewer through the device to a varying degree depending on the viewing position. The first and second patterns of elements are configured such that a first region of the device exhibits a maximum change in the degree of obstruction when the device is tilted relative to the viewer about a first tilt axis, and a second region of the device exhibits a maximum change in the degree of obstruction when the device is tilted relative to the viewer about a second tilt axis which is not parallel to the first tilt axis.