An optical device is disclosed, comprising; a colour shifting layer that exhibits different colours dependent on the angle of incidence of incident light, and; an array of substantially transparent microstructures covering at least a part of the colour shifting layer and configured to modify the angle of light incident to, and reflected from, the colour shifting layer, said array of microstructures arranged in accordance with a plurality of pixels of a colour image to be exhibited by the optical device, each pixel exhibiting a uniform colour, wherein; the array of microstructures comprises at least first and second sub-arrays of microstructures corresponding to respective first and second colour channels, each sub-array covering an area within a pixel corresponding to the proportion of the respective colour channel within the pixel such that the pixel exhibits the uniform colour, and further wherein; the microstructures of the first sub-array are configured to modify the angle of light incident to, and reflected from, the colour shifting layer in a first manner such that, at a substantially normal viewing angle of the optical device, the first sub array exhibits a base colour and at a first viewing angle of the optical device, the first sub-array exhibits a first colour, wherein said first viewing angle corresponds to viewing the optical device along a direction that is off the normal of the optical device and; the microstructures of the second sub-array are configured to modify the angle of light incident to, and reflected from, the colour shifting layer in a second manner different to the first such that, at a substantially normal viewing angle of the optical device, the second sub-array exhibits said base colour and at said first viewing angle, the second sub-array exhibits a second colour different from the first colour; such that at a substantially normal viewing angle, the optical device exhibits the base colour, and at said first viewing angle, the optical device exhibits the colour image. Methods of manufacturing such optical devices are also disclosed.

An optical device is disclosed, comprising; a colour shifting layer that exhibits different colours dependent on the angle of incidence of incident light, and; an array of substantially transparent microstructures covering at least a part of the colour shifting layer and configured to modify the angle of light incident to, and reflected from, the colour shifting layer, said array of microstructures arranged in accordance with a plurality of pixels of a colour image to be exhibited by the optical device, each pixel exhibiting a uniform colour, wherein; the array of microstructures comprises at least first and second sub-arrays of microstructures corresponding to respective first and second colour channels, each sub-array covering an area within a pixel corresponding to the proportion of the respective colour channel within the pixel such that the pixel exhibits the uniform colour, and further wherein; the microstructures of the first sub-array are configured to modify the angle of light incident to, and reflected from, the colour shifting layer in a first manner such that, at a substantially normal viewing angle of the optical device, the first sub array exhibits a base colour and at a first viewing angle of the optical device, the first sub-array exhibits a first colour, wherein said first viewing angle corresponds to viewing the optical device along a direction that is off the normal of the optical device and; the microstructures of the second sub-array are configured to modify the angle of light incident to, and reflected from, the colour shifting layer in a second manner different to the first such that, at a substantially normal viewing angle of the optical device, the second sub-array exhibits said base colour and at said first viewing angle, the second sub-array exhibits a second colour different from the first colour; such that at a substantially normal viewing angle, the optical device exhibits the base colour, and at said first viewing angle, the optical device exhibits the colour image. Methods of manufacturing such optical devices are also disclosed.

The present invention is directed to an anti-counterfeiting device comprising a first sensor configured to undergo a first user perceptible change in response to a first biologically produced stimulus that emanates directly from a biological source; and a second sensor configured to undergo a second user perceptible change in response to a second biologically produced stimulus that emanates directly from the biological source. The second biologically produced stimulus is different than the first biologically produced stimulus.

The present invention relates to the field of and processes and printing apparatuses for producing optical effect layers (OEL) comprising magnetically oriented platelet-shaped magnetic or magnetizable pigment particles on a substrate. In particular, the present invention relates to processes using printing apparatuses comprising a first magnetic-field-generating device mounted on a transferring device (TD) and a static second magnetic-field-generating device for producing said OELs as anti-counterfeit means on security documents or security articles or for decorative purposes.

The present invention relates to the field of and processes and printing apparatuses for producing optical effect layers (OEL) comprising magnetically oriented platelet-shaped magnetic or magnetizable pigment particles on a substrate. In particular, the present invention relates to processes using printing apparatuses comprising a first magnetic-field-generating device mounted on a transferring device (TD) and a static second magnetic-field-generating device for producing said OELs as anti-counterfeit means on security documents or security articles or for decorative purposes.

The present invention provides a security film (100) with dual color shift characteristics, the security film (100) comprising a substrate layer (110) having a first substrate surface (112) and a second substrate surface (114), a first liquid crystal layer (120), including a first liquid crystalline material, disposed above the first substrate surface (112), and a second liquid crystal layer (130), including a second liquid crystalline material, disposed above the second substrate surface (114). The first liquid crystal layer (120) and the second liquid crystal layer (130) are adapted to exhibit dual color shifts, on rotation and/or translation of the security film (100). Also, a method (200) for manufacturing the security film (100) has also been provided.

The present invention provides a security film (100) with dual color shift characteristics, the security film (100) comprising a substrate layer (110) having a first substrate surface (112) and a second substrate surface (114), a first liquid crystal layer (120), including a first liquid crystalline material, disposed above the first substrate surface (112), and a second liquid crystal layer (130), including a second liquid crystalline material, disposed above the second substrate surface (114). The first liquid crystal layer (120) and the second liquid crystal layer (130) are adapted to exhibit dual color shifts, on rotation and/or translation of the security film (100). Also, a method (200) for manufacturing the security film (100) has also been provided.

The invention relates to an optical structure (5) having a relief effect, comprising: - a support (7) adapted for aligning liquid crystals, - a deposit (9) in contact with the support of a substance in the form of at least one pattern (11), which partially covers the support, and - a liquid crystal layer (13) which at least partially covers the support and said pattern and is in contact with the support.

The invention relates to an optical structure (5) having a relief effect, comprising: - a support (7) adapted for aligning liquid crystals, - a deposit (9) in contact with the support of a substance in the form of at least one pattern (11), which partially covers the support, and - a liquid crystal layer (13) which at least partially covers the support and said pattern and is in contact with the support.

An authenticity determination viewer including a first phase difference film, a linear polarizer, and a second phase difference film in this order, wherein a polarized light transmission axis of the linear polarizer and a slow axis of the first phase difference film are non-parallel to each other, and the polarized light transmission axis of the linear polarizer and a slow axis of the second phase difference film are non-parallel to each other.