Thomas Edison first received a rudimentary lamp patent in 1879. He initially used the element platinum, because it could produce white light for an extended period of time and had a high melting point. Since then, other elements have been used in light bulbs because they are more efficient, less expensive and more readily available.
Incandescent bulbs create light by the resistance of electricity through a fine filament, which causes them to get very hot when in use. Most incandescent bulbs use tungsten as a filament element. Tungsten is an inexpensive metal that has a long lifespan as a filament. It is a suitable option for incandescent bulbs because it has an extremely high melting point and is flexible. Pliable tungsten filaments are easily formed and hold up well against temperatures as high as 4,500 degrees Fahrenheit. Incandescent bulbs also contain other elements, such as argon and nitrogen, in gaseous states.
When incandescent light bulbs are manufactured, they are filled with an inert gas to insulate the filament and prevent its sublimation. The pressure inside a freshly manufactured light bulb is something like 80% of the normal atmospheric pressure. The gases normally used are argon and a little bit of nitrogen.
Inner surfaces of fluorescent light bulbs are normally covered with phosphor. Fluorescent bulbs typically contain elements such as mercury and argon gas in them. Electricity that flows through fluorescent tubes sparks ultraviolet energy via mercury vapors, and the light that we can see is formed when this energy bounces off the phosphor coating inside the tube.
Halogen light bulbs typically contain tungsten filaments in them as well as other elements in gaseous states. For example, inert elements such as fluorine, chlorine, bromine and iodine are commonly found in halogen bulbs. These elements are also called halogens and form halides when combined with other elements.
Metal Halide Bulbs
These bulbs are strong, high-output light sources that are typically used on roadways and for other outdoor purposes. Elements such as mercury and iodine are used to produce light in this type of bulb. Iodine is one of the inert or halogen elements, and when it is combined with a metal, the resultant compound is called a metal halide.