Osram Halo Star Maxi Spot AR70 - 41990 FL

The Halo Star AR series of aluminium reflector halogen lamps was introduced by Osram in the late 1970s, consisting of two version - the AR48 'Mini Spot' having a 2-pin base, and the AR70 'Maxi Spot' having a more convenient bayonet cap. It is not known if this bayonet capped lamp was first introduced by Osram, or if it was an adaptation of the rather similar Philips AR56 lamps, which were also available in the late 1970s. In 1984 the Osram AR48 and AR70 were joined by the large AR111 'Super Spot' as a 6V 35W product for very narrow beams, but rapidly expanded to higher wattage 12V lamps for projection of light over long distances.

This particular lamp comprises a novel design feature which was first introduced by Osram, in the form of the anti-glare shield positioned directly above the halogen capsule. This is obviously based on the sealed beam PAR lamps such as the popular #4515 pinspot. It absorbs uncontrolled light rays which would normally exit the capsule without being controlled by the reflector, which can otherwise gives rise to acute glare. A drawback of this original shield design was that customers would often hold the lamp at this point, and distort its position during lamp installation.

In 1982 an improved anti-glare shield was introduced, having a black surface to further limit undesirable surface reflections and with greatly increased mechanical strength. At the same time the peened surface of the reflector of this lamp was changed to a specular mirror, made possible by changing the filament position from transverse to axial so as to achieve better uniformity of luminous intensity distribution. That change also resulted in a notable increase of luminous intensity vs this original design lamp.
Manufacturer: Osram GmbH 41990FL
Lamp Power: 50 Watts  
Lamp Voltage: 12 Volts  
Lamp Current: 4.17 Amperes  
Cap Type: B15d Ni plated + Vitrite insulator
Bulb Type: AR-70 AR-22 in eighths/inch
Bulb Finish: Quartz Capsule Aluminium reflector
Filament Type: C-6 Transverse Single Coil
Atmosphere: Bromine, Krypton
Luminous Flux: N/A  
Luminous Efficacy: N/A  
Luminous Intensity: 2,200 cd  
Beam Distribution: 30° to 50% peak
Colour Temperature & CRI: CCT: 3000K CRI: Ra 100
Chromaticity Co-ordinates: CCx: 0.452 CCy: 0.409
Lifetime: 2000 hours to 50% survival
Burning Position: Universal  
Overall Length: 50 mm 2 inches
Light Centre Length: N/A  
Factory: Eichstätt Germany
Date of Manufacture: 1980 Q2 Date Code: im8
Original Value:  
References: 1) Osram Catalogue, 1985/86 Germany, p.17
2) Osram Catalogue, 1984 English, p.14
3) Wotan Halo Star Brochure, c.1987, UK
4) AEG-Telefunken Ontladingen/Schakels v2 1979, pp.36-37
5) German Patent 8,219,740U1 - Reflektorlampe, bestehend aus Reflektor und Halogenglühlampe - 1982