ENGELHARD PATENTS
MULTI-LAYER EFFECT PIGMENT
Patent No. U.S. 6,875,264 B2
Engelhard Corp. has received a
patent for a multilayer effect pigment
comprising a transparent substrate
having a layer of a transparent high
refractive index material, at least one
pair of transparent layers, one of
which is a high refractive index material
and the other of which is a low
refractive index material, wherein the
total number of layers is an odd number,
each layer differs in refractive
index from any adjacent layer by at
least approximately 0.2 and wherein
at least one layer has an optical thickness
which is different from all of the
other layers, whereby the pigment is
not a quarter-wave stack.