Optical security device offering 2D image

摘要

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.

主权项

1. A diffractive element comprising a diffractive optical microstructure comprising 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 comprises a plurality of optical elements with specifically prescribed groove shapes combining to form a three-dimensional pattern of the structure, wherein any one of the grooves is described by a continuously varied parameterized functions employing at least two parameters which vary between the grooves of the structure to form the said three-dimensional pattern, wherein the parameters are selected from a group consisting of groove shape, position, center and line thickness, and wherein the functions further serving to describe functional dependencies which are variables of a positional coordinate of the optical element.