US Patent 11187834 Multi-colored dielectric coating

A multi-color dielectric coating is formed using interleaved layers of dielectric material, having alternating refractive index, to create reflections at selected wavelengths, thus appearing as different colors. Etching of selected layers at selected locations changes the color appearance of the etched locations, thus generating a coating having multiple colors. The thicknesses of the layers are chosen such that the path-length differences for reflections from different high-index layers are integer multiples of the wavelength for which the coating is designed.