US Patent 10048411 Optical effect structures

The present invention provides an optical coating structure (10) applied to the surface of an object. “Scattering structures” are introduced to the basal, upper or middle layers of a multilayer reflector to cause a particular (calculated) degree of scattering, or to the surface of a black/color pigmented object to cause either enhanced transmission at the environment-object interface or omni-directional (as opposed to directional) reflections of which only a narrow portion can be observed. The scattering structures are mainly sub-micron in size, and arranged in a pseudo-random or non-periodic manner so as to prevent significant diffraction by themselves. Consequently they serve only to broaden the angular range of the light reflected at the surface normal from a multilayer reflector, or to provide (actual and/or perceived) reduced reflectivity of a surface by deflecting incident light through the surface rather than away from it or by scattering otherwise beam-like (narrow-angle) reflections from a surface into a broad-angle reflection. The scattering structures may comprise profile elements (12), which are in the form of elongate bars having convexly curved sides or hemispherical rods, that are introduced to a basal layer of a multilayer reflector. The layers of the multilayer reflector follow the convex curve of the bars or rods to form a distorted reflector structure.