| 摘要 |
The identification mark is in the form of an image made on a polished surface of an item, which image can be rendered optically visible and is in the form of a diffraction structure made up, in particular, of microscopic lines with a sinusoidal profile, which, in combination, form a diffractive raster image of the mark. The diffraction structure is spatially arranged in the manner of a reflective phase diffraction grating, which functions as a means for increasing contrast and altering the hue of the radiation spectrum as the image of the mark is visualized at the angle of diffraction in reflected light. Furthermore, the microstructures of the diffraction structure are formed at a depth not greater than the acceptable size of microscopic irregularities in the polish of precious stones. The proposed valuable item has a polished surface with a marking in the form of an identification mark.
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