Patent ID: 9630368
Date: 2017-04-25
CPC Classifications: B29D,G02B

Claim:
1. A method of forming a multi-spectral filter element comprising a plurality of sub-filters each adapted to respond to electromagnetic radiation within respective ones of a plurality of spectral bands, the method comprising: forming an optical cavity layer comprising at least N spatial regions on a substrate, N being a positive integer number greater than or equal to three, the optical cavity layer being a solid dielectric layer and having an initial thickness of x and forming one continuously joined base for the plurality of sub-filters; and selectively removing at least a portion of the optical cavity layer to reduce the initial thickness of the optical cavity layer in at least three of the N spatial regions, each of the N spatial regions corresponding to a respective one of the plurality sub-filters, the plurality of sub-filters comprising at least N sub-filters, wherein the selectively removing comprises an integer number of removal steps greater than or equal to the binary logarithm function Log