2 November 1993 Color neutral rugate filters
Author Affiliations +
This paper describes a transmissive rugate filter which is designed to reflect a portion of the visible spectrum and yet not appear to have a dominant color. The filter design criteria were chosen so that the filter rejects portions of the visible spectrum from 0.38 to 0.78 microns. Observing a scene through this type of optical filter one perceives it to be devoid of coloration, i.e., color neutral, albeit it is somewhat darker. The design constraints assume a solar light source. The eye bounds the wavelength range over which perceived coloration is affected. For this work the spectral characteristics of both the incident light and the standard human eye determine the nature of the spectral tailoring of the reflection bands. Rugate filter design and fabrication technology permits a very wide latitude in the number, location, bandwidth, and peak height of all reflection bands. The result is a color neutral rugate filter having reflection bands tailored to provide the human user with maximum color discrimination capability.
© (1993) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Walter E. Johnson, Walter E. Johnson, Robert L. Crane, Robert L. Crane, } "Color neutral rugate filters", Proc. SPIE 2046, Inhomogeneous and Quasi-Inhomogeneous Optical Coatings, (2 November 1993); doi: 10.1117/12.163543; https://doi.org/10.1117/12.163543


Back to Top