The Introduction to LED Lighting
Time : Jan 07 2015Source :analogtechnologies Author : Analog Click :
After Edison invented the carbon incandescent lamp in 1879, lighting technology entered a new era. Reviewing the lighting history of the twentieth Century, people found out many new light sources, such as fluorescent lamps, mercury lamps, high/low pressure sodium lamps, metal halide lamps, compact fluorescent lamps, high frequency electrode less fluorescent lamps, microwave sulfur lamps and so on. Defects of the incandescent lamp are that the bulb is fragile, and it is easy to get an electric shock and power consumption of the tungsten wire is high under the condition of heating. Although fluorescent lamps save more energy than incandescent lamps, but it is not good for human vision and the mercury in the lamp tube is harmful to human body and environment. LED causes qualitative changes of lighting technology. Compared with the traditional lighting technology, LED is a semiconductor, which can convert electrical energy into visible light. LED belongs to the solid cold light source. The volume of LED is small, its weight is light and the structure is also very solid. Because of low working voltage, service life of LED is long. In accordance with the definition of light effect, LED luminous efficiency is not high, but because almost all of the LED spectra concentrate in the visible light spectrum, the efficiency can reach 80%~90%. However, visible efficiency of incandescent lamp of the same light effect is only 10%~20%. Generally, the power of the monomer LED is 0.05~1W and LED can meet different needs through the cluster mode.
The source characteristics of LED are as follows.
(1) A new type light source of green environmental protection: Using cold light sauce, glare of LED is small, and there is no radiation and no harmful substance in use. Adopting DC drive mode, the power consumption of LED is very low and the electro-optical power conversion can be almost up to 100%. Comparing with the traditional light source, LED energy can save about 80% under the condition of the same lighting effect. Environmental benefits LED is good because there is no ultraviolet ray and infrared ray in the spectrum, no pollution and no mercury. In addition, waste of LED can be recycled and it can be safe to touch.
(2) Long life: As a solid cold light source, using epoxy resin encapsulation, LED has vibration resistance and there is no loose part in the light body. The service life can be up to 6 -10 million hours because there is no filament burn ability, thermal deposition, depreciation and other shortcomings. The service life of LED is 10 times more than the traditional light`s.
(3) Multi-transformation: Based on the principle of three basic colors and under the control of the computer, LED has 256 levels of gray which can be mixed arbitrarily, and they can produce 256×256×256（16777216） colors to form different colors combination. Multi-transformation of LED can realize the colorful dynamic changes and various image effects.
(4) High and new technology：Compared with the luminous effect of traditional light source, LED light source is microelectronic products of low voltage and it has succeeded in fusing computer technology, network communication technology, image processing technology, the embedded control technology etc.