The present invention relates to a security element (1), comprising: an optical system, comprising: a transparent or translucent substrate (2), on the side of a first surface (2a, 2b) of the substrate (2) is a combined image (I) comprising a plurality of encoded interleaved images (I1), a exposing screen (4) placed on top of the combined image, enabling the encoded images (I1) to be observed during a change in the direction of observing the security element (1) relative to the optical system, the exposing screen (4) being: located on the side of the first surface (2a, 2b), the combined image then being located between the exposing screen (4) and the substrate (2), in which case the security element (1) comprises, on the side of the second surface (2a, 2b), a reflective surface that enables the encoded images (I1) to be observed through exposing screen (4).