The principle of LED lamp

2018-10-23 10:00:02

LED (Light Emitting Diode), a light-emitting diode, is a solid-state semiconductor device that converts electricity directly into light. The heart of the LED is a semiconductor chip, one end of which is attached to a bracket, one end is a negative electrode, the other end is connected to the positive pole of the power supply, so that the entire chip is encapsulated by epoxy resin. Semiconductor wafers consist of three parts, one of which is a P-type semiconductor, in which holes predominate, and the other is a N-type semiconductor, with electrons in the first place, usually one to five cycles in the middle. When an electric current passes through a wire acting on the chip, electrons and holes are pushed into a vector well, where electrons recombine with holes, and then energy is declared in the form of photons. This is the principle of LED luminescence. The wavelength of light, also known as the color of light, is determined by data that constitutes a P-N junction.


The core of the LED is a wafer composed of p-type semiconductor and n-type semiconductor. There is a transition layer between p-type semiconductor and n-type semiconductor, called p-n junction. In some PN junctions with semiconductor data, when a small number of injected carriers recombine with a large number of carriers, the remaining energy is released in the form of light, thus directly converting electrical energy into light energy. PN junction plus reverse voltage, a small number of carriers difficult to inject, so it does not shine.


The diode made by the principle of injection electroluminescence is called light-emitting diode, commonly known as LED. When it is in a positive operating condition (i.e. with a positive voltage at both ends), the current flows from the LED anode to the cathode, the semiconductor crystal announces different colors of light from ultraviolet to infrared, and the intensity of light depends on the current.


The first principle of full-color LED is: red-green-blue color mixing to complete seven color changes, the output waveform pulse width modulation, that is, adjust the duty cycle of LED light conduction, in the case of fast scanning speed, the use of human visual laziness to achieve mutation.