| 摘要 |
957,042. Discharge lamps. PATENT-TREUHAND-GESELLSCHAFT FUR ELECTRISCHE GLUHLAMPEN m.b.H. May 11, 1960 [May 15, 1959 (2); Aug. 11, 1959], No. 16621/60. Heading H1D. A composite electric lamp comprises an outer envelope 1, a first incandescent filament 16 and a H.P. discharge lamp 9 mounted within the envelope, the discharge lamp comprising a light-transmissive bulb, two main electrodes 13 and a gaseous atmosphere producing an operating pressure of about 1 atmosphere and less than 2 atmospheres, a second incandescent filament 10 mounted within the bulb, and series semiconductor resistors 14, 15. Within the envelope 1 connecting the second incandescent filament in parallel with the arc discharge path, the series resistors having negative temperature coefficients. The filament 10 can be a single- or multiple-coiled filament and can act as a starting electrode. The envelope 1 is formed of glass transparent to U.V. light above 300 mÁ. The atmosphere in the discharge lamp comprises a metal vapour, such as mercury or cadmium, and/or an inert gas, such as neon or argon, at a pressure of 10-1200 mm., preferably 100-300 mm. The incandescent filament 16 acts as a current limiting resistance and I.R. source. A third incandescent filament 17, acting as a source of I.R. radiation, is contained within the envelope 1 and is connected to the supply arrangement 20, 21, 22, 23 so that it can be operated independently of the discharge lamp 9, the discharge lamp 9 and filament 16 having about the same wattage as the filament 17. One or more differently coloured glow lamps 24 indicate whether the discharge lamp 9 or the filament 17 is being operated. The electrodes 13 are connected to molybdenum foils 11 and the filament 10 is supported at 12 on the discharge lamp 9 and connected through other foils 11 to the resistors 14, 15 which are in heatconductive relationship with the discharge lamp 9. The ratio of the resistance of the resistors 14, 15 in the cold state to the resistance in the hot state during operation is between 3: 1 and 300:1, preferably 100:1, and the resistors are operable with a voltage drop of 5- 20 volts in the hot resistance condition. The envelope 1 has a neck portion 2 and an adjacent paraboloid-shaped reflector portion 3 provided with an inner reflector coating 4 of aluminium deposited by vaporization. The neck portion 2 and reflector portion 3 are coated externally with a protective layer 5 which is impervious to light and can be an enamel lacquer or aluminium. The bowl portion 6 is coated on its inner surface with frosting, and the envelope 1, or at least the bowl portion 6, can be provided with coloured inner or outer coatings, or the bowl portion 6 can be formed of coloured glass. The envelope 1 is filled with nitrogen or a mixture of 80% argon and 20% nitrogen at a pressure of about 650 mm. |
