Abstract: The present invention provides for a diffractive element comprising a diffractive optical microstructure consisting of a modulated structure of a diffractive type which upon illumination by diffused ambient light creates a two-dimensional image to be viewed by an observer upon tilting or rotating the device or by varying lighting direction, wherein the diffractive modulated structure of the device consists of various generally parameterised special optical elements with specifically prescribed groove shapes, wherein each groove shape, position, center(s), and line thickness, are described by functions describing those dependencies which are variables of the positional coordinate of the optical element.

Abstract: The invention provides for both a composite image field for verification and/or security applications and including a plurality of sets of image elements, wherein members of each set are from the same one of a respective plurality of images and are spaced and located within the composite image in a manner seeking to avoid those of another set, the composite image being formed by the adjacent location of the spaced elements and wherein the spacing and location is in a defined manner serving to create a security key; and also a related composite optical element for verification and/or security applications and including a plurality of sets of optical elements, the members of each set sharing die same optical properties and spaced and located within the composite element in a manner seeking to avoid those of another set, the composite optical element being formed by the adjacent location of the spaced elements and wherein the spacing and location is in a manner defined for providing a security key.

Abstract: The present invention provides for a diffractive structure comprising a plurality of grooves each formed by a plurality of two-dimensional scattering and/or diffractive groove elements, aligned in a manner serving to provide for at least one diffractive optical effect and further a surface display device comprising a plurality of regions wherein each region has a diffractive surface relief structure as defined above and wherein the gratings of one of said regions at an angle relative to the gratings of another of said regions.

Abstract: The present invention provides for a diffractive element comprising a diffractive optical microstructure consisting of a modulated structure of a diffractive type which upon illumination by diffused ambient light creates a two-dimensional image to be viewed by an observer upon tilting or rotating the device or by varying lighting direction, wherein the diffractive modulated structure of the device consists of various generally parameterised special optical elements with specifically prescribed groove shapes, wherein each groove shape, position, centre(s), and line thickness, are described by functions describing those dependencies which are variables of the positional coordinate of the optical element.