a structural frame having an inner and an outer perimeter, an inner perimeter front holding a front fixing apparatus, and an outer perimeter holding a back fixing apparatus, wherein the front fixing apparatus and the back fixing apparatus are spaced relative to each other leaving a variable gap;

a luminescent layer or material with a high level of light transmission with an outer surface and an inner surface secured by the front fixing apparatus, said front fixing apparatus having a cavity for housing a linear LED light source, and a reflector element being secured by the back fixing apparatus, wherein the linear LED light source housed inside the front fixing apparatus cavity emits light towards the interior of the luminescent layer wherein the inner surface has been intervened by scratches or cuttings to allow for the light that goes through the interior of the luminescent layer to exit from said intervened inner surface towards the reflector element, the light then being reflected on said reflector element and to be refracted on the luminescent layer, wherein said reflector element is a deformed, non-straight sheet for obtaining a luminescent effect on the surface of the luminescent layer.