Osram Metal Halide Power Stars HQIL 400W
Osram's first metal halide lamp was the HQIL 400W of 1965, based on the same sodium-thallium-indium (NTI) chemistry as the original GE and Philips products. Its outer bulb was coated with magnesium fluoro-germanate phosphor. Just like competitors lamps it suffered problems of excessive colour variations and short life. It was quickly de-listed while only the larger 2000W version was offered for sale - the higher wattage lamps being rather easier to produce.

At the end of 1968 Osram re-introduced the lamp on this page, and solved the colour variation issues by shifting from NTI to Rare Earth (RE) chemistry. The arc tube is dosed with dysprosium iodide, delivering a multi-line spectrum of high colour rendering quality. Thallium iodide is added to bring the colour point onto the blackbody locus, and since the RE discharges tend to be constricted and as a result rather unstable, caesium iodide is used as an arc-fattening agent. Depsite the reduced proportion of UV radiation, it still has a phosphor coating whose red fluorescence is visible after starting. However when fully run up there is almost no discernable radiation from the phosphor.

The X-Ray reveals the novel conical-ended arc tube shaped from 3 quartz pieces, and heat reflector-coated ends to help increase halide vapour pressures. A heat reflector disc is present in the lamp neck, and large barium getters hold the outer under high vacuum. No hydrogen getter is present. At the end of 1968, to improve life and stability, it was replaced by two variants optimised for vertical or horizontal use, along with clear tubular versions. Since the phosphor had little purpose, that was quickly replaced by an ordinary diffuse coating and the name changed from HQIL to HQI.
Manufacturer: Osram GmbH
Lamp Power: 350 Watts
Lamp Current: 3.5 Amps
Lamp Voltage: 120 Volts
Cap Type: E40s/45 Ni plated brass + porcelain
Bulb Type: ED-120 ED-37 in eighths/inch
Bulb Finish: Phosphor coated Borosilicate
Electrodes: Backwound Tungsten No emitter
Arc Length: 48 mm 1 7/8 inch
Atmosphere: DyI3,TlI,CsI | Ar:Kr85 Outer: Hard Vacuum
Luminous Flux: 26,000 lm @ 100 hours
Luminous Efficacy: 74.3 lm/W @ 100 hours
Colour Temperature & CRI: CCT: 5600K CRI: Ra 85
Chromaticity Co-ordinates: CCx: 0.328 CCy: 0.393
Rated Lifetime: 6,000 hours to 70% flux
Warm-up & Re-strike Time: 2 mins to 80% flux 10-15 minutes
Burning Position: Universal
Overall Length: 292 mm 111/2 inches
Light Centre Length: 196 mm 73/4 inches
Factory: Berlin-Entwicklung Germany
Date of Manufacture: 1968 September Date Code: gaZ
Original Value: DM 116/- (1968)
 
References: 1) Osram Lampenkatalog, Germany, Oktober 1965.
2) Osram Lampenkatalog, Germany, Januar 1968.
3) Osram Lampenkatalog, Germany, Oktober 1968.
4) Osram Brochure HQI 400W, November 1968.
5) Osram Brochure Q-M-Na Entladungslampen, Februar 1969.
6) Osram Brochure Q-M-Na Entladungslampen, Januar 1972.
7) Osram Power Stars Technical Manual, August 1984.
8) Metal Halide Lamps with Rare Earth Additives, A. Dobrusskin, Lighting Research & Technology V.3 No.2 (1971) pp.125-132.
9) Halogen-Metalldampflampen mit Seltenen Erden, A. Dobrusskin & H. Leyendecker, Technisch-wissenschaftliche Abhandlungen der Osram-Gesellschaft, Vol.11 (1973) pp.163-188.
10) Photometry Measurement.