A security element for the production of value documents, such as banknotes, checks or the like, said security element comprising - a dielectric substrate, - a first line grid structure embedded in the substrate, consisting of several grid bars located in a plane and extending along a longitudinal direction, and a second line grid structure embedded in the substrate, consisting of second grid bars extending along the longitudinal direction, wherein - the first grid bars each have a width and are juxtaposed at a distance, such that first grid gaps extending along the longitudinal direction are formed between the first grid bars which first grid gaps have a width corresponding to the distance, - the second line grid structure is inverted to the first line grid structure, wherein, seen in plan view on the plane, the second grid bars are located above the first grid gaps and second grid gaps, which exist between the second grid bars, are located above the first grid bars, and - the widths of the first grid bars and of the second grid gaps, the widths of the second gird bars and of the first grid gaps and thicknesses (t) of the first grid bars and of the second grid bars are each less than 300 nm, - the first and second grid bars (3, 7) either consist of metal or semiconductor or of a multilayer coating, and - the second grid bars are located completely above the grid bars relative to the plane, such that the first and second line grid structures (2, 6) do not form a continuous film, wherein the dielectric substrate embedding the line grid structures (2, 6) comprises a base layer, a dielectric intermediate layer and a dielectric cover layer, and wherein - the first line grid structure is formed on the base layer, - the dielectric intermediate layer is applied thereon, which covers both the first grid bars and the first grid gaps, said layer being thicker than the first grid bars, - the second line grid structure being formed thereon, and - the dielectric cover layer is arranged over the second line grid structure, characterized in that the intermediate layer, the cover layer and the base layer substantially have the same refractive index. - a dielectric substrate, - a first line grid structure embedded in the substrate, consisting of several grid bars located in a plane and extending along a longitudinal direction, and a second line grid structure embedded in the substrate, consisting of second grid bars extending along the longitudinal direction, wherein - the first grid bars each have a width and are juxtaposed at a distance, such that first grid gaps extending along the longitudinal direction are formed between the first grid bars which first grid gaps have a width corresponding to the distance, - the second line grid structure is inverted to the first line grid structure, wherein, seen in plan view on the plane, the second grid bars are located above the first grid gaps and second grid gaps, which exist between the second grid bars, are located above the first grid bars, and - the widths of the first grid bars and of the second grid gaps, the widths of the second gird bars and of the first grid gaps and thicknesses (t) of the first grid bars and of the second grid bars are each less than 300 nm, - the first and second grid bars (3, 7) either consist of metal or semiconductor or of a multilayer coating, and - the second grid bars are located completely above the grid bars relative to the plane, such that the first and second line grid structures (2, 6) do not form a continuous film, - the first line grid structure is formed on the base layer, - the dielectric intermediate layer is applied thereon, which covers both the first grid bars and the first grid gaps, said layer being thicker than the first grid bars, - the second line grid structure being formed thereon, and - the dielectric cover layer is arranged over the second line grid structure, characterized in that the intermediate layer, the cover layer and the base layer substantially have the same refractive index.