| 摘要 |
374,305. Electric incandescent lamps. GENERAL ELECTRIC CO., Ltd., Magnet House, Kingsway, London.-(Assignees of Patent-Treuhand-Ges. fur Elektrische Gluhlampen ; 11, Ehrenbergstrasse, Berlin.) July 7, 1931, No. 19576. Convention date, Aug. 8, 1930. [Class 39 (ii).] In electric lamps of the kind provided with a filling of gas with the addition of one or more metal vapours through which an electric discharge passes in parallel with the current passing through the filament of the lamp the filament is provided with electron emitting material along substantially the whole of its operative length, the electron emitting material being in the form of a coating upon the core of the filament, or being intimately mixed with the material from which the filament is made, or in the form of a small rod around which a wire is wound. In the example a pair of leading-in wires 5 carried by the pinch 4 support a spirally wound filament 6 provided with a central supporting wire 7 sealed into the pinch. The lamp bulb 1 is filled with a gas such as argon, helium, neon, nitrogen or carbon dioxide, or a mixture such as of argon and helium at three millimetres pressure. The lamp bulb also contains a vaporizable metal such as sodium, potassium, cadmium, magnesium or mercury, which may be introduced in the form of a coating inside the bulb, but is preferably provided by a small pool 8 at the bottom of the bulb. The electron-emitting material may comprise a mixture of alkali or alkaline earth metal compounds. Upon switching on the lamp the pool 8 of metal is vaporized by the heat of the filament and a glow discharge in parallel with the filament is initiated, the discharge soon changing to an arc which emits the greater proportion of the light. |
