LED lighting

- Jun 18, 2019-

1.Lighting principle:

LED light source, LED by Ⅲ - Ⅳ compounds, such as GaAs (gallium arsenide), GaP (gallium phosphide), GaAsP phosphorus (GaAs) made of semiconductor, such as its core is the p-n junction. Therefore, it has the i-v characteristics of the general p-n junction, that is, positive guide pass, reverse cut-off and breakdown characteristics. In addition, under certain conditions, it also has the characteristic of luminescence. At forward voltage, electrons are injected into P region from N region and holes into N region from P region. Some of the minority carriers (minority carriers) entering the opposite region compound with most carriers (multiple carriers) to glow.

Assuming that the luminescence occurs in the p-region, then the injected electron is directly combined with the valence band hole to emit light, or it is captured by the luminescence center and then combined with the hole to emit light. In addition to this luminous recombination, some electrons are captured by the non-luminous center (which lies between the conduction band and the dielectric band), and then recombined with the hole, each time releasing little energy to form visible light. The higher the ratio of luminescent recombination to non-luminescent recombination, the higher the quantum efficiency. Because the recombination is luminescent in the region of few - particle diffusion, the light is produced only within micron near the PN junction.

Theoretical and practical evidence suggests that the peak wavelength of light is dependent on bandgap Eg, or lambda ≈1240/Eg (mm).

Where, the unit of Eg is electron volts (eV). If visible light can be generated (wavelength of 380nm violet light ~ 780nm red light), the semiconductor material Eg should be between 3.26 and 1.63eV. Wavelengths longer than red light are infrared light. There are infrared, red, yellow, green and blue light emitting diodes, but the cost and price of blue light diodes are very high.


High energy saving: energy saving and no pollution means environmental protection. Dc drive, ultra-low power consumption (single tube 0.03-0.06 watt), high electro-optical power conversion, the same lighting effect than the traditional light source energy saving.

Long life: some people call it longevity lamp, which means the lamp that never goes out. Solid cold light source, epoxy resin package, there is no loose part in the lamp body, there is no filament light easy to burn, heat deposition, light decay and other shortcomings, the service life can reach 60,000 to 100,000 hours, more than 10 times longer than the traditional light source life.

Multi-variation: LED light source can use the principle of red, green and blue primary colors. Under the control of computer technology, the three colors have 256 levels of grayscale and can be mixed arbitrarily. 256×256×256=16777216 colors can be generated.

Benefit for environmental protection: environmental protection benefits are better, there is no ultraviolet and infrared ray in the spectrum, no heat, no radiation, and waste can be recycled, no pollution, no mercury elements, cold light source, can be safely touched, is a typical green lighting source.
