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Proceedings Paper

Spectral And Angular Selectivity Of Obliquely Deposited Films
Author(s): Rogath T. Kivaisi
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Paper Abstract

We report on coatings which exhibit both spectral and angular selectivity. These coatings are prepared by oblique electron-beam or resistive heating evaporation of Ge and Cr onto glass substrates. Transmittance measurements in the 0.35 - 20 pm range showed a remarkably high absorption in the solar spectrum combined with transparency in the infrared region. Typical results for a 140 nm thick chromium film deposited on aluminium or chromium substrate gave a solar absorptance value higher than 0.90 and a normal emissivity value of 5 to 12 % depending on the type of metal backing. These coatings were found to be stable in air at 250°C, which make them satisfactory for both flat plate and low concen-tration collectors producing low and medium grade heat. Thin films (-70 - 100 nm) showed interesting features when transmission measurements were made at various angles of incidence. They showed high transmission when rotated in one direction but low when rotated in the opposite direction, hence exhibiting an angular selectivity.

Paper Details

Date Published: 1 December 1983
PDF: 6 pages
Proc. SPIE 0428, Optical Materials and Process Technology for Energy Efficiency and Solar Applications, (1 December 1983); doi: 10.1117/12.936297
Show Author Affiliations
Rogath T. Kivaisi, Institute of Optical Research (Sweden)


Published in SPIE Proceedings Vol. 0428:
Optical Materials and Process Technology for Energy Efficiency and Solar Applications
Carl M. Lampert, Editor(s)

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