Abstract: An optical element, e.g. based on a diffractive Fresnel lens, having suppressed or reduced chromatic aberration under non-monochromatic light and/or enhanced directional homogenisation in its angular irradiation characteristics, comprises a plurality of optical zones (10, 20), wherein each zone comprises at least one homogenising noise-introducing feature. In embodiments the at least one homogenising noise-introducing feature comprises one or more zonal displacement features, e.g. ripples (20?, 20?) and/or one or more zonal modulation features, e.g. one or more patterning features (30).

Abstract: An optical element, e.g. based on a diffractive Fresnel lens, having suppressed or reduced chromatic aberration under non-monochromatic light and/or enhanced directional homogenisation in its angular irradiation characteristics, comprises a plurality of optical zones (10, 20), wherein each zone comprises at least one homogenising noise-introducing feature. In embodiments the at least one homogenising noise-introducing feature comprises one or more zonal displacement features, e.g. ripples (20?, 20?) and/or one or more zonal modulation features, e.g. one or more patterning features (30).

Abstract: An optical element, e.g. based on a diffractive Fresnel lens, having suppressed or reduced chromatic aberration under non-monochromatic light and/or enhanced directional homogenisation in its angular irradiation characteristics, comprises a plurality of optical zones (10, 20), wherein each zone comprises at least one homogenising noise-introducing feature. In embodiments the at least one homogenising noise-introducing feature comprises one or more zonal displacement features, e.g. ripples (20?, 20?) and/or one or more zonal modulation features, e.g. one or more patterning features (30).

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.