Light Source Degradation

Light source degradation is the gradual decrease over time of output signal with constant input light level. As the output decays the focal spot size increases over time.

Mercury vapor lamps rarely burn out completely but suffer from depreciation as the output decays and focal spot size increases over time thus becoming ineffective while still drawing the same amount of power as when they were new, as well as decreased light output the warm-up time will be increased considerably.

Some of the more advanced mercury lamp based systems integrates a technology which logs the lamp operation hours and maintains lamp temperature to increase lamp life.