On the main streets of the city, many trees have been wrapped with LED strips for decorative lighting. People can't help but be amazed at their dazzling figures, but never know the inside story of why they glow. So, do you understand the working principle of led strips? What is the working principle of Led light bar?
From the perspective of LED strip lighting, LED lights are made by encapsulating GaN chips and yttrium aluminum garnet (YAG). The GaN chip emits blue light (λp=465nm, Wd=30nm), and the Ce3+-containing YAG phosphor made by high temperature sintering emits yellow light with a peak value of 550nm after being excited by this blue light. The blue LED lamp substrate is installed in a bowl-shaped reflective cavity, covered with a thin layer of resin mixed with YAG, about 200-500 nm. Part of the blue light emitted by the LED lamp substrate is absorbed by the phosphor, and the other part of the blue light is mixed with the yellow light emitted by the phosphor to obtain white light. Now, for InGaN/YAG white LED lamps, by changing the chemical composition of the YAG phosphor and adjusting the thickness of the phosphor layer, various colors of white light with a color temperature of 3500-10000K can be obtained. This method of obtaining white light through blue LED lamps has the advantages of simple structure, low cost, and high technical maturity, so it is widely used. This is one of the principles of LED strip light.
From a physical level, the electrons in an atom have many energy levels. When the electrons jump from a high energy level to a low energy level, the energy of the electron is reduced, and the reduced energy is converted into photons and emitted. A large number of these photons are lasers. However, the difference is that LEDs do not emit light through electronic jumps inside atoms, but by applying a voltage across the PN junction of the LED to make the PN junction itself form an energy level (actually, a series of energy levels). level), and then electrons jump at this energy level and produce photons to emit light. When the current acts on the wafer through the wire, the electrons will be pushed to the P region, where the electrons and holes recombine, and then emit energy in the form of photons, which is the principle of LED light. The wavelength of light, which is also the color of light, is determined by the material that forms the P-N junction. This is also one of the principles of LED strip lighting.
