
3.4 High-Pressure Discharge Lamps 79
A variation of the high-pressure mercury vapor lamp is the super-high-pressure
mercury lamp (200 Atm) that does not employ a secondary outer tube and is used
in projectors for image and video displays (Figure3.44; spectrum in Figure3.45;
and characteristics in Table3.13). In this case, the mercury emission lines are
strongly broadened due to the high pressure (pressure broadening) and cover the
entire visible spectrum, resulting in a high-intensity white light with no need for
uorescent powders.
Yet another variation is the hybrid lamp that combines the mercury vapor dis-
charge and incandescence (Fi