| 摘要 |
<p>An electrode for a discharge lamp is formed, which has an improved adhesion between the emitter material and the filament. A filament made of an Fe-Cr-Al alloy is placed in a heated oxidising environment to precipitate an aluminium oxide layer uniformly on its surface. The thus precipitated aluminium oxide layer has good adhesion with the filament without flaking. The aluminium oxide layer is coated with triple carbonates consisting of barium carbonate, calcium carbonate and strontium carbonate, so that a carbonate coated filament is obtained. The coated filament is then heated in vacuum to reduce the carbonates to their alkaline earth oxides of the emitter material, and also to form a complex oxide consisting of the aluminium oxide and the alkaline earth oxides. Adhesion between the emitter material and the aluminium oxide layer is improved by the formation of the complex oxide, so that the lamp life of the discharge lamp is remarkably increased. On the other hand, since the Fe-Cr-Al alloy has a much higher specific resistance value than tungsten, the discharge lamp using a filament of the Fe-Cr-Al alloy can be operated by a small current, which in turn enables a lamp driving circuit that is reduced in size and weight. <IMAGE></p> |
