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During the 1980s Sylvania rolled out an Energy Saving strategy across its entire light source portfolio. The tungsten halogen lamps were of course included, and several product categories were expanded to include new higher efficacy versions. First launched was a series of double ended linear sources, employing coiled-coil filaments and gas fillings of higher pressure and higher molecular weight to realise a wattage reduction of approximately 10%. A few years later low energy MR16 lamps were introduced, with this 42W rating being promoted to replace conventional 50W lamps. However in this case there is no real efficacy increase - the light output is reduced in proportion to the wattage.
At this time Sylvania had limited MR16 display lamp production in its European and American factories, and many types were produced at Kondo Sylvania in Japan. This lamp thus shares many design features with the typical Japanese "JR" products of the time.
Unusually for such a low voltage and low wattage lamp, the filament is of a coiled-coil design. Although the coiled-coil does not bring about any substantial increase in luminous efficacy, it does permit the filament size to be reduced. A small filament is of great importance in such a compact reflector, because it helps to increase the optical efficiency of the system. It also leads to a filament of lower aspect ratio, such that the resulting beam is more circular in shape.
The reflector shows an unusual feature in that the surface is peened around the outer perimeter. This is believed to be in an effort to improve beam uniformity, as filament images are often produced mainly by this area of the reflector. |