SUBSTANCE TO MARK AUTHENTICITY OF BANK NOTES, SECURED PAPERS AND DOCUMENTS AND METHOD OF ITS PREPARATION Russian patent published in 2011 - IPC B41M5/00 G06K1/12 

FIELD: printing industry.

SUBSTANCE: invention relates to the field of protection of bank notes, secured papers and documents and may be used to manufacture marks, containing active centres of nitrogen-vacancy in nanocrystals of diamond, to apply them in the form of substance on specified objects to verify authenticity of the latter. Substance of marks represents suspension containing nanocrystals of diamond with centres of nitrogen-vacancy (NV centres) and liquid carrier. Specified liquid carrier represents a dissolvent, for instance, propanol, which includes stabiliser substance preventing aggregation (sticking) of specified diamond nanocrystals, for instance, of 0.5-5.0 wt % of polyvinyl pyrrolidone. Diamond nanocrystals represent nanocrystals of natural and/or synthetic diamonds modified so that there is a concentration of specified NV centres in them in the range from 10¹⁷ to 10¹⁹ units in cm³, and at that concentration of nanocrystals in specified suspension makes 3-10·10^-4 g/ml.

EFFECT: invention provides for increased extent of marks protection, and also higher accuracy of their verification authentication.

3 cl, 1 ex