Dulux 'F' Flat Compact Fluorescent

The F-style family of compact fluorescent lamps were first developed by Osram, and effectively the lamp is a half length version of the L-type long CFLs. Its compact form made it an alternative to the popular 2D product created a few years earlier by Thorn Lighting. Owing to Thorn's strong patents on the 2D shape it was not possible for competitors to enter that market with a lamp of the same shape.

The Osram solution does not achieve the same illuminated area as 2D, especially in higher wattage types, but is successful in presenting a similarly efficient and compact flat fluorescent lamp. In fact an advantage of the Osram design is that it provides a more uniform illuminated area, without the dark central region of 2D. However this does increase its operating temperature somewhat, with a subsequent loss of efficacy as compared to the 2D shape.

This lamp was assembled at Osram's Bari factory in Italy according to the unique glass forming method employed there, which also formed the basis of the glassworking for the subsequent Endura electrodeless lamp. Effectively the method of joining the two limbs of the discharge tube is a larger version of the cut-and-kiss technique, in which the join occupies the entire tube diameter. Two U-tubes are created and then sealed together in a planar arrangement with a small bridge join above the base. A considerable dead length of discharge tube remains in the base, this forming a cold spot and helping to maintain high lamp efficacy.

This F-shape lamp has not been a commercial success on the scale of the 2D product and today accounts for only a very small share of the compact fluorescent market.
Manufacturer: Osram GmbH
Lamp Power: 18 Watts
Lamp Current: 0.375 Amps @ 50Hz 0.320 Amps @ HF
Lamp Voltage: 58 Volts @ 50Hz 50 Volts @ HF
Cap Type: 2G7
Bulb Finish: Triphosphor 830
Bulb Type: 4T-16 4T-16 (in eighths / inch)
Length: 122 mm 4¾ inches
Width: 17.5x79mm 3/8 x 3 1/8 inches
Discharge Length:
Electrodes: Triple Coil Tungsten Triple Carbonate Emitter
Atmosphere: Ar,Kr | Hg
Luminous Flux: 1,100 lm @ 100 hours
Luminous Efficacy: 61.1 lm/W @ 100 hours
Colour Temperature & CRI: CCT: 3000K CRI: Ra 85
Chromaticity Co-ordinates: CCx: 0.440 CCy: 0.402
Burning Position: Universal
Rated Lifetime: 10,000 hours Rated to 50% survival
Warm-up / Re-strike Time: 2 minutes Instant
Factory: Bari Italy
Date of Manufacture: May 1993
Original / Present Value:
References: 1) Osram UK Brochure "Osram Dulux Compact Fluorescent Lamps" July 1993.