The present invention relates to a method for creating a hidden pattern on a substrate, wherein a liquid treatment composition comprising at least one acid is deposited by inkjet printing onto a substrate, which comprises at least one external surface comprising a salifiable alkaline or alkaline earth compound.

The present invention provides photoluminescent iron-doped barium stannate materials absorbing ultraviolet (UV) light and exhibiting strong near-infrared (NIR) luminescence. Such materials exhibit increased integrated photoluminescence intensity in comparison to known BaSnO.sub.3 and iron-doped barium stannate materials, and therefore they are particularly useful for the production of photoluminescent security ink compositions and transparent covert security features with improved anti-counterfeiting resistance that can be used for protection of documents and articles against counterfeit and illegal reproduction.

The present invention provides photoluminescent iron-doped barium stannate materials absorbing ultraviolet (UV) light and exhibiting strong near-infrared (NIR) luminescence. Such materials exhibit increased integrated photoluminescence intensity in comparison to known BaSnO.sub.3 and iron-doped barium stannate materials, and therefore they are particularly useful for the production of photoluminescent security ink compositions and transparent covert security features with improved anti-counterfeiting resistance that can be used for protection of documents and articles against counterfeit and illegal reproduction.

An identification apparatus or system includes an estimation unit that estimates an operating distance between the surface of an optical device and an imaging unit as an estimated value. A reference distance refers to the distance between a first face of an identification target and the imaging unit and at which light diffracted by a diffraction grating is capable of being recorded by the imaging unit. A first determination unit is included that determines whether the estimated value matches the reference distance and a second determination unit that determines whether an image captured by the imaging unit matches a reference image. Conditions for identifying the optical device as the identification target include a condition that the first determination unit determines that the estimated value matches the reference distance and a condition that the second determination unit determines that the image captured by the imaging unit matches the reference image.

A secure substrate may include a base layer and an opacity layer disposed above the base layer. An optional background layer may be disposed above the opacity layer. The secure substrate may further include an inkjet receptive layer. A first inkjet receptive layer may be disposed above the background layer, and a second inkjet layer may be disposed below the base layer. The opacity layer may include copper such as metallic copper flakes or other particles. The opacity layer may also include a binder material such as polyvinyl alcohol, and in some cases also carbon black, process black, or the like.

A secure substrate may include a base layer and an opacity layer disposed above the base layer. An optional background layer may be disposed above the opacity layer. The secure substrate may further include an inkjet receptive layer. A first inkjet receptive layer may be disposed above the background layer, and a second inkjet layer may be disposed below the base layer. The opacity layer may include copper such as metallic copper flakes or other particles. The opacity layer may also include a binder material such as polyvinyl alcohol, and in some cases also carbon black, process black, or the like.

In an optical structure for displaying a stereoscopic frame image on a structure formation surface, a frame motif that displays a frame image in which reflection moves is formed on a structure formation surface, the frame motif is made up of a plurality of perforated reflecting segments, each including one or more first reflecting mirrors having a reflective layer uniformly tilted relative to the structure formation surface, the tilt angle of the first reflecting mirror is different between adjacent perforated reflecting segments so as to gradually change over a plurality of adjacent perforated reflecting segments, and at least one of the plurality of perforated reflecting segments surrounds an opening provided with no first reflecting mirror.

In an optical structure for displaying a stereoscopic frame image on a structure formation surface, a frame motif that displays a frame image in which reflection moves is formed on a structure formation surface, the frame motif is made up of a plurality of perforated reflecting segments, each including one or more first reflecting mirrors having a reflective layer uniformly tilted relative to the structure formation surface, the tilt angle of the first reflecting mirror is different between adjacent perforated reflecting segments so as to gradually change over a plurality of adjacent perforated reflecting segments, and at least one of the plurality of perforated reflecting segments surrounds an opening provided with no first reflecting mirror.

Products, such as branding labels, credit cards, and currency, that are fabricated so as to include an optical security element, which is designed to provide enhanced optical focusing onto each color used in the printed image (or in the ink layer). The optical security assembly may include a carrier film or substrate. An image element, e.g., a printed ink layer, is provided on a first surface of the carrier film/substrate, and the optical security assembly further includes an array or plurality of micro lenses on a second surface of the carrier film/substrate opposite the image element (when the substrate/carrier film is transparent). In order to make the registration and print requirements easier, pixels are isolated into sections of the printed ink layer, which can then be arranged to align with sets of lenses (i.e., each set/group of lenses may be dedicated to focusing upon a particular color of ink).

Products, such as branding labels, credit cards, and currency, that are fabricated so as to include an optical security element, which is designed to provide enhanced optical focusing onto each color used in the printed image (or in the ink layer). The optical security assembly may include a carrier film or substrate. An image element, e.g., a printed ink layer, is provided on a first surface of the carrier film/substrate, and the optical security assembly further includes an array or plurality of micro lenses on a second surface of the carrier film/substrate opposite the image element (when the substrate/carrier film is transparent). In order to make the registration and print requirements easier, pixels are isolated into sections of the printed ink layer, which can then be arranged to align with sets of lenses (i.e., each set/group of lenses may be dedicated to focusing upon a particular color of ink).