Article capable of creating a moire effect

摘要

An article, illustratively a lamp bulb envelope, for creating a moire effect has a plurality of transparent and nontransparent regions on its surface. When viewed from a point external to the envelope, the individual nontransparent regions on the surface of the envelope which is nearest to the point appear as superimposed upon and intersecting with nontransparent regions on the surface furtherest from the point. The apparent intersections produce a moire effect which is enhanced by varying the line of sight to the bulb. The family of moire curves appear as transversely running curves which pass through the points of apparent intersection of individual nontransparent regions along the near and far faces. The nontransparent regions may be either light diffusive (translucent) or light nontransmissive (opaque) in nature and may be created by abrading the surface of the envelope or by application of opaque or diffusive coatings onto the surface of the envelope. When an actual filament, arranged within the envelope, is energized to emit light, an apparent filament appears in inverted relationship with the actual filament within the envelope.