Method and apparatus for controlling fluorescent lamp mercury vapor pressure

摘要

A fluorescent lamp light output is maximized by cooling the cathode regions. Mercury vapor pressure is maintained at an optimum or desired level for light production by cooling the cathode areas of the lamp. The cooled cathode areas of the lamp collect cathode emissive material and mercury vapor condensates. Thus, the light output remains uniform and constant. The functional length of the lamp is not degraded by the deposition of either cathode material or mercury vapor condensates. Cooling can be effected by forcing cool air against the exterior of the lamp adjacent the cathodes or by using forced water heat exchangers. By cooling the respective cathode regions equally, the amount of deposition in the respective regions is substantially the same. Thus, gradations of deposition are avoided. The constant high output fluorescent lamp can be used with electronic inspection equipment and machine vision measurement devices. The inspection equipment and machine vision devices can detect signals with a single photodetector or an array of photodetectors. Optical fiber receivers and transmitters can be used to deliver a reflected light signal or image to associated electronic processing equipment.