| 摘要 |
PURPOSE:To reduce change in the chromatic characteristics due to dimming and enable instant starting and restarting by encapsulating a rare gas and metal halides in a light emitting tube fitted internally with a pair of electrodes on which a pulse voltage is impressed controllably. CONSTITUTION:A high pressure discharge lamp 1 is internally fitted with a pair of electrodes 3a, 3b in a light emitting tube 2 made of quartz and connected with an external starter circuit 7 and a current control circuit 8, pulse circuit 9 through leads 4a, 4b of molybdenum foils 6a, 6b. Rare gas such as Xe, Kr, etc., and metal halides are encapsulated in the light emitting tube 2, and no mercury encapsulated. Therefore, it is possible to reduce change of the chromatic characteristics resulting from mercury even though the dimming is generated by a plurality of dimming switch boards 10 provided in the pulse circuit 9. Because the rare gas is already gasified, it does not require the time for evaporation to allow performing instant starting, and this does not use any large quantity of mercury which might give an obstruction for the start. and restarting can take place with a low pulse voltage. |
