11 November 1996 Optical charaterization of black appliques
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For some stray light applications, it may be advantageous to use a black applique rather than a conventional black coating. Appliques consist of a free-standing sheet of black material and an adhesive or other means for attaching the applique to a substrate. In this paper the optical scatter in the visible and infrared of black appliques from Battelle, Dupont, Edmund Scientific, Energy Science Laboratory, Inc. (ESLI), Rippey and Rodel is reported and compared to Martin Black. The Rippey and Rodel appliques are sold as polishing cloths for the semiconductor industry, whereas the ESLI applique was originally developed as a low sputter yield coating. The Battelle applique consists of a carbon loaded polyurethane film with a surface which is heat molded into a micro-grooved pattern. The ESLI applique consists of high aspect ratio fibers mounted in an adhesive base and was the blackest applique of all those investigated. For an incidence angle of 10 degrees, a scattering angle of 45 degrees and a wavelength of 632.8 nm, the BRDF of the best ESLI applique was 3 multiplied by 10-4, compared to 1 multiplied by 10-3 for the best Battelle applique, 1.5 multiplied by 10-3 for a representative Martin Black sample and 1.8 multiplied by 10-3 for the Edmund applique. The Battelle applique is quasi-diffuse due to its surface microstructure, with a higher BRDF (2-5 multiplied by 10-3) at scatter angles less than 15 degrees For a wavelength of 10.6 micrometer, an incidence angle of 7.5 degrees and a scatter angle of 45 degrees, the BRDF of the ESLI coating (1 multiplied by 10-3) was slightly higher than Martin Black (8 multiplied by 10 -4), with the Battelle applique exhibiting strong dependences on scatter angle and groove orientation. In the 2 - 14 micrometer spectral range, the directional hemispherical reflectance of the ESLI coating at a 20 degree incidence angle is below 0.45% and only weakly dependent on incidence angle to 60 degrees. In- plane and cross-plane BRDF measurements at 3.39 micrometer are reported on a 'biased' ESLI coating which is designed for use at near grazing incidence. In-plane BRDF measurements at wavelengths of 0.6328 and 10.6 micrometer are reported for most of the appliques studied.
© (1996) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Keith A. Snail, Keith A. Snail, Dennis P. Brown, Dennis P. Brown, Joseph P. Costantino, Joseph P. Costantino, Wendy C. Shemano, Wendy C. Shemano, Carl W. Schmidt, Carl W. Schmidt, William F. Lynn, William F. Lynn, Christopher L. Seaman, Christopher L. Seaman, Timothy R. Knowles, Timothy R. Knowles, } "Optical charaterization of black appliques", Proc. SPIE 2864, Optical System Contamination V, and Stray Light and System Optimization, (11 November 1996); doi: 10.1117/12.258336; https://doi.org/10.1117/12.258336

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