Lighting and displays
Turning electricity into light, from LEDs and lasers to screens.
Conversion and use · Conversion devices · No. 106
- Conversion and use
An average LED gives five times the light of a halogen bulb per watt, yet still reaches only half of physics' limit.
Chart: Illustration: Lighting and displays
Where it comes from
Chart: Map of where it comes from
Inside a white LED, electrons and holes meet in a thin indium gallium nitride layer and release blue light; a phosphor turns part of it yellow and red. Better LEDs already turn over 60% of their electricity into light.
Three things to know
- Lighting's share of world electricity has fallen from about 19% in 2000 to about 12% in 2025, mostly thanks to LEDs.
- A plain incandescent bulb manages about 16 lumens per watt; an average LED sold today gives about 100, and the best about 230.
- OLED screens light each pixel themselves, so black pixels draw no power; Samsung Display ships 54.3% of large OLED panels (2025 forecast).
The journey
- 1 Mains powerAlternating current enters the lamp
- 2 DriverConverts it to low-voltage direct current
- 3 LED chipIndium gallium nitride emits blue light
- 4 PhosphorShifts part of the blue to white
- 5 Eye or screenLumens light rooms, streets and pixels