In part, the disclosure relates to articles of manufacture, such as banknote, that include one or more precious materials formed as unitary structure and that is secured within the article and disposed below one or more tamper resistant elements such that the article is self-authenticating. The articles may include polymer-based notes, instruments and other substantially planar articles defined by a boundary and an upper surface and a lower surface such that a precious material is at least in part co-planar with a third surface sandwiched therebetween. The disclosure also relates to a flexible precious metal storage apparatus that includes three layers, one layer defines a cavity. The cavity is sized and arranged to have a precious metal layer deposited, printed, injected, grown, or otherwise at least partially surrounded by the boundary of the geometric shape.

A method of providing an Optical Variable Device (OVD) on a security document by exposing the security document with a laser. The security document includes an overlay provided on a core and the overlay includes a halogenated homo- or copolymer.

An optically variable security arrangement for securing valuable articles, comprises a first sub-element having a two-dimensional relief grid composed of a plurality of grid elements and that has, in at least one spatial direction R.sub.1, a first line screen p below 500 m, and in which the grid elements are each formed from at least two relief elements that are directionally reflective in different directions, and a second sub-element having at least one dot and/or line grid that, in a spatial direction R.sub.2, has a second line screen q. A movement effect is created by the interplay of the relief grid and the dot and/or line grid when the security arrangement is tilted.

A dielectric layer comprising an embossed surface and a flat surface which is located at a side opposite to the embossed surface is provided. The plane that approximates the flat surface is the X-Y plane, and the normal direction to the X-Y plane is the Z direction. The embossed surface has inclined surfaces that are inclined with respect to the Z direction, and the inclined surfaces reflect incident light incident on the dielectric layer and emerge reflected light. The elevation angle, which is an angle between the inclined surface and the X-Y plane, is . The refractive index of the dielectric layer is n. These values satisfy Formula (1): sin (1/n)<sin 2.

An anti-counterfeiting medium includes a recording medium, a polarizer layer arranged on a part of the recording medium. The polarizer layer is formed thereon with a low extinction-ratio area that forms an image portion where a polarizer exhibits an extinction ratio lower than in a portion other than the low extinction-ratio area of the polarizer layer. The recording medium is formed thereon with an image portion that is a part of the recording medium and has a nature different from that of a portion other than the part of the recording medium.

An anti-counterfeiting medium includes a recording medium, a polarizer layer arranged on a part of the recording medium. The polarizer layer is formed thereon with a low extinction-ratio area that forms an image portion where a polarizer exhibits an extinction ratio lower than in a portion other than the low extinction-ratio area of the polarizer layer. The recording medium is formed thereon with an image portion that is a part of the recording medium and has a nature different from that of a portion other than the part of the recording medium.

A security device is disclosed, comprising: a first ink (21) and a second ink (22) each arranged in respective laterally offset first and second regions of the security device, the first and second inks each comprising a respective luminescent material which both luminesce in response to irradiation at at least one excitation wavelength in the ultra-violet spectrum, the first and second inks each exhibiting substantially the same non-luminescent visible colour as one another when illuminated with visible light in the absence of the at least one excitation wavelength, and the first and second inks each exhibiting visible colours which are different from the non-luminescent visible colour and from one another when illuminated with a combination of visible light and the at least one excitation wavelength; a third ink (23) arranged in a third region of the device laterally offset from the first and second regions of the device, the third ink not luminescing in response to the at least one excitation wavelength, and the third ink exhibiting substantially the same non-luminescent visible colour as the first and second inks when illuminated with visible light in the absence of the at least one excitation wavelength; and a fourth ink (24) arranged in a masking pattern which partially overlaps one or more portions of the first ink in the first region and/or of the second ink in the second region, the fourth ink not luminescing in response to the at least one excitation wavelength, and the fourth ink exhibiting a different visible colour from the non-luminescent visible colour of the first, second and third inks when illuminated with visible light in the absence of the at least one excitation wavelength. When the security device is illuminated with visible light in the absence of the at least one excitation wavelength, the first, second and third regions together appear as one continuous pattern in the non-luminescent visible colour, the fourth ink obscuring the presence of more than one ink forming the continuous pattern, and when the security device is illuminated with a combination of visible light and the at least one excitation wavelength, the first and second regions become visibly distinct from each other and from the remainder of the continuous pattern.

A security device is disclosed, comprising: a first ink (21) and a second ink (22) each arranged in respective laterally offset first and second regions of the security device, the first and second inks each comprising a respective luminescent material which both luminesce in response to irradiation at at least one excitation wavelength in the ultra-violet spectrum, the first and second inks each exhibiting substantially the same non-luminescent visible colour as one another when illuminated with visible light in the absence of the at least one excitation wavelength, and the first and second inks each exhibiting visible colours which are different from the non-luminescent visible colour and from one another when illuminated with a combination of visible light and the at least one excitation wavelength; a third ink (23) arranged in a third region of the device laterally offset from the first and second regions of the device, the third ink not luminescing in response to the at least one excitation wavelength, and the third ink exhibiting substantially the same non-luminescent visible colour as the first and second inks when illuminated with visible light in the absence of the at least one excitation wavelength; and a fourth ink (24) arranged in a masking pattern which partially overlaps one or more portions of the first ink in the first region and/or of the second ink in the second region, the fourth ink not luminescing in response to the at least one excitation wavelength, and the fourth ink exhibiting a different visible colour from the non-luminescent visible colour of the first, second and third inks when illuminated with visible light in the absence of the at least one excitation wavelength. When the security device is illuminated with visible light in the absence of the at least one excitation wavelength, the first, second and third regions together appear as one continuous pattern in the non-luminescent visible colour, the fourth ink obscuring the presence of more than one ink forming the continuous pattern, and when the security device is illuminated with a combination of visible light and the at least one excitation wavelength, the first and second regions become visibly distinct from each other and from the remainder of the continuous pattern.

An optical device is disclosed, comprising: a colour layer which comprises elongate strips of at least two different colours alternating with one another periodically along a direction of colour periodicity, the elongate strips extending along the direction which is orthogonal to the direction of colour periodicity; and a light redirecting layer overlapping the colour layer, and defining at least a first image to be exhibited by the optical device. The light redirecting layer comprises at least a first array of refractive and/or reflective anisotropic light redirecting elements extending across a first region of the light redirecting layer and being absent elsewhere, the anisotropic light redirecting elements of the first array each having a primary axis orientated along a first direction lying in the plane of the optical device and being configured such that an incident light beam lying in a plane perpendicular to the first direction and from a light source off the normal of the optical device will be redirected by the anisotropic light redirecting elements towards the normal of the optical device but within the same plane, whereas an incident light beam lying in a plane which is not perpendicular to the first direction and from a light source off the normal of the optical device will either not be redirected, or will be redirected by the anisotropic light redirecting elements out of the plane of the incident light beam.

An optical device is disclosed, comprising: a colour layer which comprises elongate strips of at least two different colours alternating with one another periodically along a direction of colour periodicity, the elongate strips extending along the direction which is orthogonal to the direction of colour periodicity; and a light redirecting layer overlapping the colour layer, and defining at least a first image to be exhibited by the optical device. The light redirecting layer comprises at least a first array of refractive and/or reflective anisotropic light redirecting elements extending across a first region of the light redirecting layer and being absent elsewhere, the anisotropic light redirecting elements of the first array each having a primary axis orientated along a first direction lying in the plane of the optical device and being configured such that an incident light beam lying in a plane perpendicular to the first direction and from a light source off the normal of the optical device will be redirected by the anisotropic light redirecting elements towards the normal of the optical device but within the same plane, whereas an incident light beam lying in a plane which is not perpendicular to the first direction and from a light source off the normal of the optical device will either not be redirected, or will be redirected by the anisotropic light redirecting elements out of the plane of the incident light beam.