MULTI-LAYERED SECURITY STRUCTURE FOR FIDUCIARY USE AND SECURITY DOCUMENT USING THE STRUCTURE

The invention particularly relates to a multi-layered security structure (S) for fiduciary use, which comprises at least three different, superimposed layers which are referred to as the first upper layer (1), second intermediate layer (2) and third lower layer (3), respectively, the first layer (1) being optically variable, that is to say, having different colours depending on the angle of observation or illumination with light reflected on a dark background, and being transparent or quasi-transparent on a light background; the second intermediate layer (2) incorporating at least one thermochromic material which has a first dark colour which thus constitutes the dark background and is opaque in a first temperature range and becomes at least partially transparent at a temperature outside the first temperature range; the third layer (3) being formed by at least one pattern (30, 31) with a dark colour thereby constituting the dark background, characterised in that it comprises a transparent or translucid support material and in that the first layer (1) also forms a barrier to ultraviolet radiation.