[2] It took more than a century of continuous and incremental improvement, including numerous designs, patents, and resulting intellectual property disputes, to get from these early experiments to commercially produced incandescent light bulbs in the 1920s.

[8] William Greener, an English inventor, made significant contributions to early electric lighting with his lamp in 1846 (patent specification 11076), laying the groundwork for future innovations such as those by Thomas Edison.

The late 1870s and 1880s were marked by intense competition and innovation, with inventors like Joseph Swan in the UK and Thomas Edison in the US independently developing functional incandescent lamps.

[10][1] The turn of the century saw further improvements in bulb longevity and efficiency, notably with the introduction of the tungsten filament by William D. Coolidge, who applied for a patent in 1912.

Stimulated by this report, and with all of the key elements available, a team led by George E. Inman built a prototype fluorescent lamp in 1934 at General Electric's Nela Park (Ohio) engineering laboratory.

Bright, "A great deal of experimentation had to be done on lamp sizes and shapes, cathode construction, gas pressures of both argon and mercury vapor, colors of fluorescent powders, methods of attaching them to the inside of the tube, and other details of the lamp and its auxiliaries before the new device was ready for the public.

In its modern form, the incandescent light bulb consists of a coiled filament of tungsten sealed in a globular glass chamber, either a vacuum or full of an inert gas such as argon.

When an electric current is connected, the tungsten is heated to 2,000 to 3,300 K (1,730 to 3,030 °C; 3,140 to 5,480 °F) and glows, emitting light that approximates a continuous spectrum.

Incandescent bulbs are highly inefficient, in that just 2–5% of the energy consumed is emitted as visible, usable light.

[18] In warmer climates, the emitted heat must then be removed, putting additional pressure on ventilation or air conditioning systems.

[21] Oily residue from fingerprints may cause a hot quartz envelope to shatter due to excessive heat buildup at the contamination site.

[22] The risk of burns or fire is also greater with bare bulbs, leading to their prohibition in some places, unless enclosed by the luminaire.

Fluorescent lamps consist of a glass tube that contains mercury vapour or argon under low pressure.

The inside of the tubes are coated with phosphors that give off visible light when struck by ultraviolet photons.

[24] The solid-state light-emitting diode (LED) has been popular as an indicator light in consumer electronics and professional audio gear since the 1970s.

[32] The lamps produce significant ultraviolet output, they require ventilation when used indoors, and due to their intensity they need protection from direct sight.

They remained in use in limited applications that required these properties, such as movie projectors, stage lighting, and searchlights, until after World War II.

Some lamp types contain a small amount of neon, which permits striking at normal running voltage with no external ignition circuitry.

In the 1900s the Phoebus cartel formed in an attempt to reduce the life of electric light bulbs, an example of planned obsolescence.

Rooms with frequent switching, such as bathrooms, can expect much shorter lamp life than what is printed on the box.

[50][51][52] Lamps which emit a specific frequency of blue light are also used to treat neonatal jaundice[53] with the treatment which was initially undertaken in hospitals being able to be conducted at home.

[57] Due to their nonlinear resistance characteristics, tungsten filament lamps have long been used as fast-acting thermistors in electronic circuits.