||Prior to the development of the G9-style single ended low wattage mains voltage halogen capsule by Osram, halogen retrofits for incandescent lamps typically employed double-ended quartz inner capsules. These were too long to fit into the envelopes of some of the smaller sized decorative incandescent lamps, when assembled according to standard lampmaking methods. This was unfortunate because the decorative shaped incandescent lamps are typically sold as premium products, where customers are willing to pay a little more than for the larger utilitarian lamps used for general lighting service. It was recognised that the embodiment of halogen technology into the smaller decorative lamps would make a good fit with consumer expectations, but there simply wasn't sufficient room to fit the halogen capsules into many of these bulbs.
The first solution to the problem came from Osram, with the development of its halogen Candle types. In order to accommodate the great length of the inner double-ended halogen capsule, the conventional stem assembly of the outer bulb has been dispensed with. It is replaced by a considerably shorter small metal clip, which rigidly fixes the inner capsule to the cap. The glass bulb is not sealed and is simply cemented into the cap. Two versions were offered, in this hexagonal shaped crystalline bulb as well as a conventional twisted candle bulb.
The inner capsule is identical to other Osram halogen types, its filament being supported by quartz dimples at two points. The filament is of a segmented type, being single-coiled at the support points so as to reduce its temperature and thermal losses at these locations.