INFORMATION CARRIER Russian patent published in 1997 - IPC

FIELD: identification or credit cards or other documents which require authentication. SUBSTANCE: device has at least three layers. Middle and upper layers are made from opaque material, lower one is made from transparent or reflecting material. Said layers contain diffraction patterns in which direction, space and shape of their lines conform to condition of conversion of half of received light into spectrum of given non-zero order for each pattern and to additional condition of alignment of directions of diffracted light beams in following regions: diffraction pattern in lower layer reflects in red spectrum region, diffraction pattern in middle layer reflects in green spectrum region, diffraction pattern in upper layer reflects in blue spectrum regions. Picture which is used for authentication of information carrier is viewed at direction of reflected beams at angle of less than 45 degrees with respect to plane of information carrier. Color identification picture is generated by removal of material from parts of either upper opaque layer or both upper and middle opaque layers by means of laser engraving. EFFECT: increased reliability. 2 cl, 3 dwg