A：Unlike incandescent lamps, LEDs are not inherently white light sources. Instead, LEDs emit nearly monochromatic light, making them highly efficient for colored light applications such as traffic lights and exit signs. However, to be used as a general light source, white light is needed. White light can be achieved with LEDs in three ways:
Phosphor conversion, in which a phosphor is used on or near the LED to convert the colored light to white light
RGB systems, in which light from multiple monochromatic LEDs (e.g., red, green, and blue) is mixed, resulting in white light
A hybrid method, which uses both phosphor-converted (PC) and monochromatic LEDs.
The potential of LED technology to produce high-quality white light with unprecedented energy efficiency is the primary motivation for the intense level of research and development.