LED luminaire technical principles

　　LED is generally often called cold light source, because LED light principle is the electron through the composite photonic issued directly, without the need for a hot process. However, due to the presence of Joule heat, LED light-emitting heat while also accompany, but also for high-power LED applications and multiple occasions, calories add up and can not be underestimated, LED unlike incandescent, fluorescent and other traditional lighting light, high temperatures will shorten, or even terminate its life. And the LED is a temperature sensitive device, when the temperature rises, the sharp decline in its efficiency, so the system architecture design and cooling technology development is also required to face the issue of LED application. Forced air cooling is usually because the light source is not desirable, so as to improve the input power, heat sinks and other cooling methods enhance the natural convection in the design of LED lights and lighting play an increasingly important role.

　　At present widespread use of white LED emits blue excited by the blue LED superimposed yellow-yttrium aluminum garnet (YAG) phosphor, synthesized as white light. Because of its emission spectrum contains only blue, yellow these two spectra, so there is high color temperature, color rendering index of the problem of low, does not meet the requirements for general lighting. The sensitivity of the human eye is much higher than the color strength of the sensitivity to light, the lighting, the light source color is often more important than the luminous efficiency. Therefore, adding an appropriate amount of red fluorescent powder and to maintain a high luminous efficiency white LED lighting is an important issue.

　　Long-term traditional lamp to incandescent, fluorescent light fixtures as reference to determine the shape of the optical and standard, LED lighting system should consider adding to abandon the traditional lighting LED light module assembly methods, give full consideration to its optical properties, as LED light source designed different lamps. Optical system design mainly includes the following aspects: ① According lighting objects, flux needs, determine the shape of the optical system, LED number and size of power; ② the number of combinations designed LED light source, ring light or surface light source of the "secondary source", according to combined into a secondary light source, computing illumination optical system; ③ illumination optical system design constitutes a "secondary source" on each LED tube light distribution control is very important.