US Patent 9606272 Transparent element with diffuse reflection

This transparent layered element (1) has two smooth outer main surfaces (2A, 4A) and comprises:two outer layers (2, 4), which each form one of the two outer main surfaces (2A, 4A) of the element (1) and which are constituted of dielectric materials having substantially the same refractive index (n2, n4), anda central layer (3) inserted between the two outer layers, this central layer (3) being formed either by a single layer which is a dielectric layer having a refractive index different from that of the outer layers or a metal layer, or by a stack of layers which comprises at least one dielectric layer having a refractive index different from that of the outer layers or a metal layer.