Glass-enclosed chamber and internal venetian blind having slats of improved reflectance and diffusivity over a wider spectral interval of incident solar radiation

Abstract

Inside a glass-enclosed chamber is a Venetian blind connected to internal elements for operating it, the elements being workable from outside to raise, lower and incline the slats. The raw slats of the blind are obtained by moulding a rolled strip of aluminum alloy hardened by magnesium. The strip has not been lapped in order to maintain a degree of roughness on both surfaces, ready to receive a reflecting layer. Reflective stratification includes a layer of pure aluminum adherent to the body of the slat that serves to fix a reflective type of interferential dielectric multilayer. Average thickness of the layer of sputtered aluminum depends on the diffusivity of reflected radiation required in relation to the maximum height of the peaks of surface roughness on the body of the slats. Useful multilayers increase reflectance to levels averaging over 85% on a wide interval of wavelengths from near infrared to ultraviolet.