Patent ID: 8498033

Claim:
An optical device exhibiting a shift of color upon rotation, comprising: a substrate having an array of structures disposed thereon or therein, and a color shifting coating supported by the substrate and forming a color shifting reflector therewith, wherein the color shifting coating is disposed over the structures of the substrate; wherein each of the structures of the substrate has first and second surfaces having a line of mutual intersection forming a non-zero angle with a plane of the substrate, wherein the first and the second surfaces each have a width and a length larger than 2 microns, so that no significant diffraction of visible light occurs; whereby the shift of color of the optical device is observable by rotating the optical device in the plane of the substrate; the substrate further comprising a base layer, a planar reflector layer supported by the base layer, and an intermediate transparent layer supported by the planar reflector layer, wherein the color shifting coating is supported by the intermediate transparent layer of the substrate, and wherein the color shifting coating has a reflector layer having a plurality of voids therein arranged to form indicia discernible by color and observable at a first angle of rotation of the substrate in its own plane, when light propagates consecutively through the voids in the reflector layer, through the intermediate transparent layer, and is reflected by the planar reflector layer to propagate back through the layers in reversed order.