CYCLING CHILLED MIRROR DEWPOINT HYGROMETER INCLUDING A SAPPHIRE OPTICAL MIRROR

摘要

A cycling chilled mirror hygrometer is described wherein the mirror employed comprises a sapphire substrate having deposited thereon alternating layers of titanium dioxide and silicon dioxide. The surfaces resulting from the described technology yield a ten fold enhancement over the "theoretically pure" optical surface characteristics achieved with the prior art gold mirrors. Additionally, these devices have provided ideal surface characteristics for 350 degree optical triangulation, thereby permitting greater primary sensor sensitivity at low humidity levels (below -40 Cdp) and the elimination of long term "optical reflective gain" variations due to aging characteristics as compared with the conventional gold mirrors having impurities.