| 摘要 |
1376509 Metal vapour lamps PATENTTREUHAND-GES FUR ELEKTRISCHE GLUHLAMPEN mbH 24 March 1972 [26 March 1971] 13971/72 Addition to 1282805 Heading H1D A high pressure mercury vapour discharge lamp with an additive consisting of a halide of a rare earth metal and/or of thallium, as described in Specification 1,282,805, is characterized in that bromine is present in an amount exceeding the stoichiometric ratio by from 0À1 to 3 mg./cm.<SP>3</SP>. Preferably the excess of bromine amounts to 0À2 to 0À8 mg./cm.<SP>3</SP>, and the amount of bromides may be 0À25-10 gm./cm.<SP>3</SP>, preferably 0À5-5. The rare earth metal may comprise dysprosium, holmium and thulium, alone or in combination, and the envelope may contain 2-12 mg.Àcm.<SP>3</SP> of mercury, preferably 4-10 mg./cm.<SP>3</SP>, and may contain up to 4 mg./cm.<SP>3</SP>, preferably 3 mg./cm.<SP>3</SP>, of caesium halide such as iodide, and a noble gas. In one example the filling comprises 0À6 mg dysprosium, 0À6 mg. holmium, 5 mg. mercuric bromide, 2À4 mg. caesium iodide, 10 mg. mercury, and argon at 50 torr. The mercury bromide reacts with the rare earth metals within the discharge envelope to form their bromides with excess bromine. The lamp may comprise a single envelope without an outer envelope. |
