For the general population it must be interesting. LED (Light Emitting Diodes) are ubiquitous. We are very much familiar with LED flashlights that come with smartphones. And almost all of them tend to be white in colour. Now the interesting thing is that there are no white LEDs. LEDs are monochromatic (that is single coloured). Engineers apply clever tricks to create white light from LEDs. Mainly two methods are used:
- Mixed colour white light: In this method, an LED module actually consists of three individual LEDs emitting Red, Green and Blue lights (RGB). A combination of these three colours is perceived to be white by our eyes.
- Phosphor-converted white light : Here a blue light emitting LED is coated with a chemical (phosphor material). The phosphor emits yellow light when excited with blue light from LED. The combination of Blue and Yellow light is again perceived as white by our eyes.