Patent ID: 9562996
Date: 2017-02-07
CPC Classifications: G02B

Claim:
1. An article comprising separate first and second stacks of microlayers, the first and second stacks being arranged in series such that light transmitted by the first stack impinges on the second stack, and/or light transmitted by the second stack impinges on the first stack, the microlayers in each stack being arranged into optical repeat units; wherein, at a design angle of incidence, the first stack provides a first 1 wherein the second 2 wherein the first 1 wherein a substantial overlap is (a) having an actual overlap between a reflection band and another reflection band based on band edge wavelengths or (b) having a band edge wavelength of a reflection band differing by 5% or less than a band edge wavelength of another reflection band; and wherein a band edge wavelength for determining the substantial overlap is defined by a sufficient coherent reflectivity to achieve a reflection band having only reflectivity values greater than 25% of a peak reflectivity of the reflection band.