A security print medium for forming security documents therefrom, the security print medium comprising a core having opposing first and second sides. The core comprises a radiation-responsive substance distributed within the core across at least a first region of the core, the radiation-responsive substance being responsive to a predetermined input radiation by producing a predetermined output radiation. The security print medium further comprises a first encoding layer disposed on the first side of the core and a second encoding layer disposed on the second side of the core, each of the first and second encoding layers comprising an encoding material that modifies the intensity of the predetermined input radiation and/or the predetermined output radiation produced by the radiation-responsive substance transmitted through the respective encoding layer, wherein the first and second encoding layers overlap each other across the first region. The optical density of each of the first and second encoding layers varies across the first region in accordance with a predetermined pattern, the predetermined pattern defining one or more encoding features, such that when the security print medium is exposed to the predetermined input radiation, the output radiation detectable from one or each side of the security print medium varies across the first region in accordance with the one or more encoding features. The first and second encoding layers are configured such that when the security print medium is viewed in transmitted visible light, the intensity of visible light transmitted through the first encoding layer, the core and the second encoding layer in combination is uniform across the first region, such that the one or more encoding features is concealed.

A security print medium for forming security documents therefrom, the security print medium comprising a core having opposing first and second sides. The core comprises a radiation-responsive substance distributed within the core across at least a first region of the core, the radiation-responsive substance being responsive to a predetermined input radiation by producing a predetermined output radiation. The security print medium further comprises a first encoding layer disposed on the first side of the core and a second encoding layer disposed on the second side of the core, each of the first and second encoding layers comprising an encoding material that modifies the intensity of the predetermined input radiation and/or the predetermined output radiation produced by the radiation-responsive substance transmitted through the respective encoding layer, wherein the first and second encoding layers overlap each other across the first region. The optical density of each of the first and second encoding layers varies across the first region in accordance with a predetermined pattern, the predetermined pattern defining one or more encoding features, such that when the security print medium is exposed to the predetermined input radiation, the output radiation detectable from one or each side of the security print medium varies across the first region in accordance with the one or more encoding features. The first and second encoding layers are configured such that when the security print medium is viewed in transmitted visible light, the intensity of visible light transmitted through the first encoding layer, the core and the second encoding layer in combination is uniform across the first region, such that the one or more encoding features is concealed.

A method for verifying a security document by means of a reading device wherein first transmission and/or reflection properties of a first region of the security document are detected in a first spectral range by the reading device and a first data set specifying these properties is generated therefrom, wherein the first region at least in some regions overlaps an optical security element arranged on the security document or embedded in the security document and wherein second transmission and/or reflection properties of the first region of the security document are detected in a second spectral range by the reading device and a second data set specifying these properties is generated therefrom, wherein the first spectral range differs from the second spectral range, and wherein, the authenticity of the security document and/or of the security element is checked on the basis of at least the first data set and the second data set.

A method for verifying a security document by means of a reading device wherein first transmission and/or reflection properties of a first region of the security document are detected in a first spectral range by the reading device and a first data set specifying these properties is generated therefrom, wherein the first region at least in some regions overlaps an optical security element arranged on the security document or embedded in the security document and wherein second transmission and/or reflection properties of the first region of the security document are detected in a second spectral range by the reading device and a second data set specifying these properties is generated therefrom, wherein the first spectral range differs from the second spectral range, and wherein, the authenticity of the security document and/or of the security element is checked on the basis of at least the first data set and the second data set.

A security element comprising a first and a second pattern formed in or on a substrate is described, the first pattern (105; 205) being formed by discrete elements (105a-105g; 205a-205c) of a first material that are distributed over a first region (101) of the substrate (100; 200), the second pattern (106; 206) being formed by discrete elements (106a-106i; 206a-206c) of a second material that are distributed over a second region (102) of the substrate (100; 200), said second material being different from said first material, said first and second regions of the substrate overlapping, wherein the discrete elements of at least one of the first and second patterns are distributed randomly, a part of the discrete elements of the first pattern (105; 205) overlap with a part of the discrete elements of said second pattern (106; 206), and the security element is defined by the first pattern (105; 205), the second pattern (106; 206) and a third pattern (107; 207) associated with the overlap of some or all of the discrete elements of said first and second patterns.

In order to support the verification of a security document, the document is placed on a verification device having a touchscreen. A conductive structure embedded in the document is detected by the touchscreen and the position and orientation of a window in the document is calculated therefrom. The verification device then displays an image positioned and rotated to appear at the location of the window. The image may interact with the document to generate Moir patterns, fluorescent images or animations.

In order to support the verification of a security document, the document is placed on a verification device having a touchscreen. A conductive structure embedded in the document is detected by the touchscreen and the position and orientation of a window in the document is calculated therefrom. The verification device then displays an image positioned and rotated to appear at the location of the window. The image may interact with the document to generate Moir patterns, fluorescent images or animations.

There is provided a versatile optical element applicable both to an electrode layer required in a bank bill field and to an optical element required in an ID field. In an optical element (1) according to one embodiment of the present invention, a first layer (2) is arranged on a second layer (3) having a relief structure on a surface thereof, and a first region (4) and a second region (5) are provided. Electromagnetic waves incident at a preset specific angle from a side of the first layer (2) are totally reflected due to at least one of the relief structure in the first region (4) and a ratio of a refractive index of the second layer (3) with respect to a refractive index of the first layer (2), the electromagnetic waves incident at the specific angle from the side of the first layer (2) are not totally reflected but transmitted or refracted due to at least one of the relief structure in the second region (5) and the ratio of the refractive index of the second layer (3) with respect to the refractive index of the first layer (2), and only in case of observation performed from the specific angle on the first layer (2) side, the second region (5) has higher transparency than the first region (4), and a preset image is expressed by a transparency contrast therebetween.

There is provided a versatile optical element applicable both to an electrode layer required in a bank bill field and to an optical element required in an ID field. In an optical element (1) according to one embodiment of the present invention, a first layer (2) is arranged on a second layer (3) having a relief structure on a surface thereof, and a first region (4) and a second region (5) are provided. Electromagnetic waves incident at a preset specific angle from a side of the first layer (2) are totally reflected due to at least one of the relief structure in the first region (4) and a ratio of a refractive index of the second layer (3) with respect to a refractive index of the first layer (2), the electromagnetic waves incident at the specific angle from the side of the first layer (2) are not totally reflected but transmitted or refracted due to at least one of the relief structure in the second region (5) and the ratio of the refractive index of the second layer (3) with respect to the refractive index of the first layer (2), and only in case of observation performed from the specific angle on the first layer (2) side, the second region (5) has higher transparency than the first region (4), and a preset image is expressed by a transparency contrast therebetween.

A security element is applied to a document or an object in the form of a directly printed marking or in the form of a tag made of paper or another material, with or without an identifier. A user can take a picture of the marking or tag with a smartphone and then send the picture to a device including software provided with a recognition algorithm including neural networks. The device visualizes the fingerprint of the tag or marking, thus making it possible to ascertain the authenticity of the document or object. In order to establish the authenticity of the product protected by the device, the image, stored in a cloud or blockchain database, of the tag obtained after printing same or of the marking is compared with a new description.