Long life halogen filled tungsten filament lamp - counters temp. reduction at filament end by high thermal resistance lead wires

摘要

The halogen filled tungsten filament incandescent lamp has its filament connected to the lead-in wires by means of metal foil strips which are attached to the filament and the lead wires. This construction reduces heat transfer out of the lamp through the lead-in wires with a resulting reduction in the temperature of the ends of the filament. Such a reduction in temperature leads to attack of the filament by tungsten-halogen compounds which form at low temperature and would normally lead to a broken filament near the lead-in.