HIGH-PRESSURE DISCHARGE LAMP

摘要

PURPOSE:To facilitate discharge start and reduce restart time by providing a filament which is molded in a convex shape toward the central section of a glow tube and heating it. CONSTITUTION:Main electrodes 2 and 3 are arranged on both ends of the glow tube 1 of a high-pressure discharge lamp. One main electrode 3 is a filament which consists of a thoriated tungusten wire of 10% contents of thorium oxide, a part of which is molded in a convex shape toward the central part of the glow tube. A required amount of mercury and argon as start assisting gas are enclosed inside of the glow tube 1. A lighting devce 12 the main electrodes 2 and 3 are connected to a lighting device 12 through each lead 8 or 9 and one end of the main electrode 3 is connected to the preheating circuit of the lighting device 12 through a lead 10. When the discharge lamp is restarted, current is applied to the main electrode 3 from the preheating circuit and heated. Voltage is applied between the main electrodes 2 and 3 and discharge is started.