| 摘要 |
PURPOSE:To prevent the occurrence of a discharge lamp flickering out in a way of controlling a rise in lamp voltage, by installing a heat protective film in the base side of an end of a light emitting tube, in case of a high pressure sodium vapor discharge lamp combined with a projector for mercury-arc lamp use. CONSTITUTION:A high pressure sodium discharge device has a high pressure sodium vapor discharge lamp 1 and a projector 2 for mercury-arc lamp use as its key elements. The discharge lamp 1 is provided with electrodes as both sides, and also inside the discharge lamp, there are provided with sodium, a light emitting tube 3 in which a buffer gas metal and a starting noble gas are all sealed, a heat protective film 4 installed only in the base side of an end of the light emitting tube 3 and a vacuumed inner part by a getter 5 where the tube 3 is incorporated in. And, an outer tube 7 fitted with a base 6 and stem wires 8 and 9 are provided. In addition, a series body comprising a heater 10 and a heat responsive switch 11 consisting of a normally operated type bimetal switch is connected to a light emitting tube 2 in parallel, and a starting auxiliary conductor 12 is installed in the outer surface of the light emitting tube 3. The conductor 12 is separated away by a heat responsive switch 19. |
