Osram Dulux-S 7W Compact Fluorescent

Following the launch of Philips' PL* compact fluorescents in 1981, it immediately became clear that this would set an important new global light source standard. By late 1983 Osram had caught up, and introduced its Dulux-S equivalent.

Rather than copying the exact Philips design, Osram introduced some technical variations in an effort to reduce the cost of these lamps. Most notably it opted for a U-bend instead of the glass bridge technique. In an effort to still create something of a cold spot to decrease mercury vapour pressure and enhance efficacy to similar levels as the Philips lamps, the glass is blown into a mould having squared corners rather than a rounded bend as applied on higher wattage fluorescent lamps. The extreme outer corners of the bend serve as the cold spot, and became known as 'cold ears' when translated from their German name.

Osram also simplified the method of end sealing by eliminating several manufacturing steps. Whereas Philips applied a miniaturised glass stem-mount assembly as used on larger lamps, created by two separate seling operations, Osram was first to introduce the technique of pinch-sealing both ends of the discharge tube simultaneously to a bead-mount assembly, as used in the manufacture of miniature incandescent lamps. This is visible in the X-Ray image.

As such Osram became a cost leader in compact fluorescent, and established the design that was most copied by later competitors. It suffered a minor compromise in efficacy at higher ambient temperatures due to its slightly warmer cold spot temperature vs the Philips concept, but this was neither known nor of any real significance to most customers.
Manufacturer: Osram GmbH
Lamp Power: 7 Watts
Lamp Current: 0.175 Amps
Lamp Voltage: 45 Volts
Cap Type: G23 Aluminium + PBT
Bulb Type: T-12.4 T-4 in eighths/inch
Bulb Finish: Y2O3:Eu3+, CeMgAl11O19:Tb3+ Soda-lime glass
Electrodes: Triple Coil Tungsten Triple carbonate emitter
Atmosphere: Argon + Hg
Luminous Flux: 400 lm @ 100h
Luminous Efficacy: 57 lm/W @ 100h
Colour Temperature & CRI: CCT: 2700K CRI: Ra 81
Chromaticity Co-ordinates: CCx: 0.460 CCy: 0.414
Lifetime: 5000 hours
Warm-up & Re-strike Time: 2 minutes Instant
Burning Position: Universal
Overall Length: 137 mm 53/8 inches
Lighted Area: 100 x 27 x 12 mm 4 x 11/16 x 1/2 inches
Factory: Augsburg Germany
Date of Manufacture: 1983 October Date Code: rN4
Original Value:
References: 1) Osram Lamp Catalogue 1985 Germany p.23
2) Wotan Lamp Catalogue 1988 UK p.31
3) Die Brennlagenabhängigkeit de Lichtstrom-Temperaturverhaltens bei Dulux-Lampen, D.Hofmann, Technisch-wissenschaftliche Abhandlungen aus der Osram-Gesellschaft Band 12 (1986) pp.248-255