| abstract |
An improved high pressure mercury vapor discharge lamp having a high coloremperature together with high luminous efficacy and a high color rendering. This is accomplished by including in the filling halides of at least one of the rare-earth metals dysprosium, holmium, thulium, erbium, and terbium; together with the halides of at least one of the alkali or alkaline earth metals; and including a filtering agent for radiation in the blue spectral region. The lamp is preferably of isothermal design. The electrodes preferably contain 1-3% of Dy 2 O 3 . |