OPTICAL PROTECTIVE DEVICE FORMING TWO-DIMENSIONAL IMAGE Russian patent published in 2012 - IPC G02B5/18 

FIELD: physics.

SUBSTANCE: disclosed is a diffraction protective element having a diffraction optical microstructure consisting of a modulated diffraction-type structure. When illuminated with scattered ambient light, the structure forms a two-dimensional image which will be visible to a viewer when the device is tilted or rotated or when the direction of light changes. The diffraction modulated structure of the device consists of different, mainly parametrised optical elements with presence of specified topographic forms. Each topographic form, position, centre and line thickness are described by functions and are variable with respect to the positional coordinate of the optical element.

EFFECT: high distinguishability of a diffraction protective element, particularly in poor illumination conditions.

17 cl, 7 dwg