What is an LED?
An LED, short for light-emitting diode, functions as a semiconductor device that emits light when an electric current passes through it. By allowing the current to flow in the forward direction while blocking it in the reverse direction, LEDs enable the recombination of electrons with holes, resulting in the emission of light. LEDs are essentially p-n junctions that are heavily doped. Depending on the specific semiconductor material and level of doping, an LED emits light of a particular color at a specific wavelength when forward biased. To facilitate the emission of light, an LED is enclosed within a transparent cover.
How does an LED operate?
When the diode is forward biased, minority electrons move from the p-region to the n-region, while minority holes move from the n-region to the p-region. This migration of minority carriers leads to an increased concentration at the junction boundary. At this junction, the excess minority carriers recombine with the majority charge carriers.
What is an LED filament?
An LED filament light bulb represents a LED lamp that has been designed to mimic the appearance and light distribution of traditional incandescent bulbs, all while retaining the high efficiency of light-emitting diodes (LEDs). This is achieved by utilizing LED filaments, which consist of strings of diodes that are connected in series and resemble the filaments found in incandescent bulbs. These LED filament bulbs can serve as direct replacements for conventional clear (or frosted) incandescent bulbs. They share the same envelope shapes, bases that fit into standard sockets, and operate at the same supply voltage. LED filament bulbs can be chosen for their appearance, closely resembling the glow of a clear incandescent bulb when illuminated, or for their wide angle of light distribution, typically spanning 300°. Additionally, they offer superior efficiency compared to many other types of LED lamps.
The following is the general structure of the LED filament:
