RLOD#40 (2020.07.02) 2015 Osram HRI 330W

Osram’s Sirius HRI is a UHP-like mercury short-arc lamp filled with a mix of molybdenum, zirconium, and hafnium halides for the color correction of the highly loaded mercury arc. Those additives improve the light color quality via two mechanisms: the selective optical emission from incandescent metal nanodroplets formed by condensation in a zone of supersaturated vapor close to the hot arc core, and the emission of a multitude of atomic lines across of the visible spectrum. The light emitted by the 330 W HRI shown here is characterized by a CRI of 86 Ra8, a color rendering which is about 29 Ra8 points higher than that of UHP lamps and the highest level of any metal halide lamps in this category. The tradeoff, however, is a lumen efficacy reduced by about 22 %, which is acceptable given the application. Like UHP lamps, the HRI is built with a precisely aligned elliptical mirror which collects, control and projects the emitted light very efficiently and accurately. The electrode gap length in the HRI 330W is 1.0 mm only, which results in an average plasma power density of 2.0 MW/cm³ and in a source brightness in the Gcd/m² range, levels unmatched in any standard metal halide short-arc lamps. Those characteristics make such lamp particularly useful in narrow-beam spotlighting applications (moving head and pinspot projectors).