High-pressure discharge lamp with incandescing metal droplets
AssigneeU.S. Philips Corporation
InventorsRobert P. Scholl, Bernhard R. Weber
Life of this patent
Estimating the term…
Abstract
The high-pressure discharge lamp has a filling in a discharge vessel (1) which includes a rare gas and a metal compound (2) chosen from hafnium halides and zirconium halides. The halide evaporates and discomposes to form incandescent, condensed metal particles. The lamp may be electrodeless and may in addition contain a buffer gas as a component of its filling. Alternatively, the lamp may have internal electrodes (13) and contain mercury (12) as a buffer gas. The lamp has favorable light generating properties, in particular a good color rendering, and in addition may have a very high luminous efficacy.
Claims16
A high-pressure discharge lamp comprising a light transmitting discharge vessel sealed in a gas-tight manner and a filling in said discharge vessel comprising a metal compound and a rare gas, wherein said metal compound evaporates during normal operation and decomposes to form condensed metal particles which generate light by incandescent emission, characterized in that:
- the metal compound is chosen from the group consisting of halides of hafnium and halides of zirconium.
An electrodeless high pressure discharge lamp, comprising:
- a light transmissive discharge vessel sealed in a gas-tight manner, said discharge vessel being free of discharge electrodes therein;
- and
- a discharge sustaining filling within said discharge vessel, said filling comprising a rare gas at a pressure of no more than 30 mbar at room temperature, a metal compound chosen from the group consisting of halides of hafnium and halides of zirconium, and a buffer gas at a pressure of between 2 and 40 bars during lamp operation,
- during lamp operation with a stable discharge, said metal compound undergoing a cycle by which it evaporates and decomposes to form condensed metal droplets, the metal droplets being heated by the discharge to incandescence by which the droplets emit light.
An electroded high pressure discharge lamp, comprising:
- a light transmissive discharge vessel sealed in a gas-tight manner, said discharge vessel including a pair of opposing tungsten discharge electrodes between which a gas discharge takes place during lamp operation;
- and
- a discharge sustaining filling within said discharge vessel, said filling comprising a rare gas at a pressure of no more than 30 mbar at room temperature, a metal compound chosen from the group consisting of halides of hafnium and halides of zirconium, and a buffer gas at a pressure of between 2 and 40 bars during lamp operation,
- during lamp operation with a stable discharge between said tungsten discharge electrodes, said metal compound undergoing a cycle by which it evaporates and decomposes to form condensed metal droplets, the metal droplets being heated by the discharge to incandescence by which the droplets emit light.
Dependencies are inferred from the claim text.