Charles wheatstone observed the spectrum of an electric discharge in mercury vapor in 1835 and noted the ultraviolet lines in that spectrum.
Metal halide mercury lamp spectrum.
A metal halide lamp is an electrical lamp that produces light by an electric arc through a gaseous mixture of vaporized mercury and metal halides compounds of metals with bromine or iodine it is a type of high intensity discharge hid gas discharge lamp.
Developed in the 1960s they are similar to mercury vapor lamps but contain additional metal halide compounds in the quartz arc tube.
The lamp uses mercury vapor to create the powerful light like the high pressure mercury vapor but includes other metals halide salts to improve the color.
Usually they re rated with a high lumen output of around 100 lm per watt a lamp life of up to 20 000 hours and pretty decent degradation rates.
A halogen is a monovalent element which readily forms negative ions.
Some manufacturers mix the metal halide technology with others to improve light output and add a few variations into the color spectrum for a more complete solution.
In 1860 john thomas way used arc lamps operated in a mixture of air and mercury vapor at atmospheric pressure for lighting.
These lamps feature special chemical compounds known as halides that produce light in most regions of the spectrum.
The german physicist leo arons 1860 1919 studied mercury discharges in 1892 and developed a lamp based on a mercury arc.
Metal halide salts exhibit lower vapor pressures than the elemental mercury added to the bulb which also serves as a buffering gas to determine the operating voltage of the lamp.
They offer high efficacy excellent color rendition long service life and good lumen maintenance.
1 how it works.