LOW-PRESSURE MERCURY VAPOUR DISCHARGE LAMP WITH FOLDED DISCHARGE PATH

摘要

1 PHN 9030 Low-pressure mercury vapour discharge lamps of the fluorescent type are known which comprise two nesting glass members so grooved as to provide between their nesting surfaces a circuitous ("folded") discharge path between two electrodes, the length of the discharge path being considerably greater than the physical distance between the electrodes. The whole surface of each glass member is coated with luminescent material with the result that, when the lamp is in use, the portions of the members not surrounding the discharge appear dark due to their poor light transmissibility. According to the invention, these portions of the two members are not coated with luminescent material and thus act as windows for light generated in the luminescent layers facing the lamp axis. Preferably, a fluted reflector is provided inside the lamp.