| abstract |
The high-pressure metal halide discharge lamp has tungsten electrodes (2) in a light-transmitting lamp vessel (1) which is closed in a vacuumtight manner. The electrodes (2) comprise an emitter which is distributed throughout their mass and is formed by a first oxide chosen from hafnium oxide and zirconium oxide and by a second oxide chosen from yttrium oxide, lanthanum oxide, cerium oxide and scandium oxide, and are substantially free from thorium oxide. The lamp retains its initial light output to a high degree throughout its life. |