What is luminous principle of led bulbs

LED light-emitting diodes (leds) is a kind of energy can be transformed to visible light solid state of semiconductor devices, it can be directly put DianZhuan into light. The heart of the LED is a semiconductor chip, chip attached on a bracket, at the end of the end is negative, the other end to connect the power of positive, make whole chip is encapsulated by epoxy resin. Understand leds luminous principle must know its hard conditions. LED lamp production is mainly III - in the first place IV family of compounds, such as gallium arsenide, gallium arsenide gallium phosphide, phosphorus and other compounds, its center is the p-n junction.

p type semiconductor has a lot of positively charged hole and the negatively charged ionization miscellaneous, because the effect of electric field, the ionized impurity is fixed, the holes are mobile. And n-type semiconductor inside there are a lot of negative and positive ions, fixed because of the effect of electric field, positive ion is fixed, it is removable. If plus forward voltage to PN junction, P type the positive side, the N type negative side, the direction of current activities from P to N, whereas holes and free electrons from moving interface, make the space charge region Narrows, current will pass. If to PN junction with reverse voltage, holes and free electrons away from the interface, make the space charge region wide and current will not pass.

so the poles and forward voltage in a semiconductor chip, some the p-n junction of compound semiconductor materials the majority carrier and a small amount of carrier, compound when the rest of the energy release in the form of light, and then complete the conversion of electrical energy to light energy. If add reverse voltage, it is hard to injection, a small amount of carrier then no carrier compound, no residual energy release, and unable to complete the conversion of electrical energy to light energy. This is the luminous principle of LED lights. Leds can replace incandescent lamp as a new generation of lighting lamps and lanterns, it is incandescent lamp does not have a lot of advantages, such as high efficiency and energy saving, use safety, small volume, strong maneuverability, green environmental protection, using the advantages such as long service life and stable luminous become fukui, lighting lamps and lanterns in modern society and traditional lighting lamps and lanterns is quit the stage of history.

1, the principle of LED dimmer has three

principle 1: wave width control dimmer ( Pulse Width Modulation, PWM) Will power square-wave digital and manipulation of the square wave duty ratio, and then reach the purpose of control current.

principle 2: constant current power supply control with analog linear skills can easily adjust the current range.

principle 3: grouping adjustment will be more than LED group, with a brief burster regulation.

2, LED the luminous process includes three parts:

under the forward bias of carrier injection, compound radiation and light transmission. Tiny semiconductor chip is encapsulated in the pure epoxy resin content, while the electrons through the crystal, negatively charged electrons move to the positively charged hole area and complex, with disappearance of electrons and holes with photons. Energy (between electrons and holes Band gap) Is larger, the higher of the photon energy. Photon energy, in turn, and the color of the light, the spectrum of visible light range, blue light, purple light with more energy, less orange colored light, red light energy. Because different materials with different band gap, which can then be announced that different colors of light.

the mainstream of LED lamps and lanterns lighting light source will be high brightness white LED. Now, the commercialization of white LED is two wavelengths more, namely to blu-ray single chip with yellow phosphor YAG mixed white light. A promising future is white LED three wavelength, namely to chip inorganic uv light red, blue, and green three color phosphor mixed white light, it will replace fluorescent lamp, compact energy-saving fluorescent light bulbs, LED back light store, etc.