||In view of the immense popularity of incandescent lamps having Neodymium bulbs in North America, a special version of the Philips Halogèna lamp was created in 2004 with this specially tinted glass envelope. The Neodymium bulb filters out a portion of the yellow wavelengths, and thereby causes the resulting light emission to enhance blues and reds - accompanied by an efficay drop of approximately 25%. This lamp was only manufactured in a 120V version exclusively for sale in North America. The concept was not marketed elsewhere owing to the fact that electricity prices are higher, and the efficacy drop which accompanies these filtered lamps generally makes them prohibitively expensive to run.
The rest of the lamp construction is identical to the standard Halogèna range of Philips. At its heart is a high efficacy coiled-coil filament. In this later model lamp there is no spiral support coil around the filament. Instead the filament is supported by the dimpled-bulb technique as invented by Osram, and swiftly copied by Philips. In the Philips design however the coil is made in one continuous segment, and heat losses are considerable at the point where the quartz touches the coiled-coils. Competitive designs achieve somewhat higher efficacy by leaving a small gap in the coil at the support points so as to minimise heat loss.
The capsule is made in quartz and incorporates fusing chambers at its pinched ends, to rapidly quench any arcing that may develop on filament failure. Additional monel fuses are provided inside the stem of the outer bulb. This permits the use of a thin-walled soft glass outer bulb of much lower cost and simpler construction than competing American designs using hardglass capsules and outer bulbs.