Security document including a transparent window formed in the substrate thereof

A security document (02) including a transparent window (04) formed in the substrate (26) thereof;

• a micro-optical structure (03) composed of microlenses (11) being arranged on one side of the substrate (26), at least in the region of the transparent window (04), and at least one print image (27) being arranged on the other side of the substrate (26), located opposite this micro-optical structure (03), at least in the region of the transparent window (04);
• the relevant print image (27) including a plurality of image elements (28a to 28j) in a punctiform or linear grid;
• a dot size (38) or a line thickness (38) of these image elements (28a to 28j) in each case being designed to be smaller than a lens width (18) of the microlenses (11) arranged in the micro-optical structure (03);
• a layer (39), which has a planar extension and covers the relevant print image (27), being arranged at least on a section of the relevant print image (27), on the side thereof facing away from the micro-optical structure (03);
• and the layer (39) covering the relevant print image (27) being created in an ink jet printing method, characterized in that this layer (39) is designed to allow electromagnetic radiation having a wavelength in the range of 380 nm to 780 nm to pass, a degree of the transparency with respect to this electromagnetic radiation being in the range between 10% and 90%;
• the transparency being designed so as to gradually vary over the two-dimensional planar extension of the layer (39) covering the relevant print image (27) so that at least one area of the layer (39) or several areas of the layer (39) is or are designed to have a different degree of transparency than other areas of this layer (39);
• a second print image (41) being arranged on the layer (39) that at least partly covers the first print image (27), on the side facing away from the micro-optical structure (03);
• and the second print image (41) being arranged on the layer (39) that covers a part of the first print image (27) in such a way that this second print image (41) can be brought into alignment with the micro-optical structure (03) applied to the other side of the substrate (26) of this security document (02), after carrying out a folding process at a bending line (07), in such a way that this second print image (41), or at least a piece of information contained therein, becomes visible and/or recognizable when viewed from the direction of the micro-optical structure (03).