The luminous principle of white LED beads is slightly different from that of other LED beads. There are currently two lighting modes that can cause LED beads to emit white light. One type is a white LED bead that uses a two wavelength "blue light+yellow light" emission mode. The basic part is a blue LED bead, which is covered with a layer of fluorescent material outside the blue emitting InGaN diode chip. When the blue light emitted by the blue LED bead chip passes through the fluorescent material, a part of it is absorbed by the fluorescent material and turns into yellow light. The yellow light then mixes with the blue light passing through the fluorescent material to emit white light. For example, some white LED beads emit pure white light, while others emit white to blue light. Another type is full-color LED beads that use a three wavelength "blue light+green light+red light" emission mode. Encapsulating red, green, and blue LED beads in the same tube can also produce white light by mixing the three primary colors of light. However, due to the relatively high cost of producing full-color LED beads, full-color LED beads are generally not used to make lighting fixtures. Full color LED beads are mainly used to manufacture full-color display screens, and using full-color LED beads to make lighting fixtures will greatly increase the cost of the product. The forward voltage drop of the white LED beads is about 3. At around 5V, it is necessary to have a forward working current of ≥ 15mA in order for it to emit light normally.