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In LED application problems and solutions

In LED application problems and solutions


In LED application problems and solutions

In current practice, the problems existing in the high power LED is mainly manifested in the following aspects:

1. To ensure that LED to poor working conditions and the cognition to the power supply technical, product on the power supply fault emerge in endlessly.

2. The application of LED street lamp today practical road concept is not clear, blind and high power gas discharge lamp “rival” regardless of the cost of production of large power LED street light, cause not practical expensive street light products to promote.

3. Feel inadequate to road lighting requirement, scientific point light source, optical light distribution, and difficult to ignore the importance of color temperature in road lighting, easy cause glare, the effect and the air pollution is serious, the rain fog weather environment, on the ground is not enough light phenomenon.

4. Fuzzy to road lighting requirement, the actual use of maintenance ill-advised, direct use of the owner of the boycott.

5. Due to the requirement for LED light source working conditions do not know much cause serious and even death lamp light attenuation.

To LED light source, the working environment the problem discussion, understand the basic knowledge of the LED is required; Light-emitting diodes (leds) at its core is the p-n junction. So it is usually I – N characteristics of p-n junction, which is the wizard, reverse blocking, the breakdown characteristic. In addition, under certain conditions, it also has a luminescence properties. Under the forward voltage, the electronic by N area into P area, hole by P area into N area. Part into the area of minority carrier (Jane) with majority carrier (children) composite and shine, its current high-power LED luminous efficiency is about 30%, 70% will be heat, needs to be heat treatment. High power white LED junction temperature of TJ in 70% intensity attenuation relationship with life we can see: TJ = 50 ℃, the life expectancy of 90000 hours, TJ = 80 ℃, the life to 34000 hours, TJ = 115 ℃, its life span is only 13300 hours. TJ in thermal design to put forward the maximum allowable TJmax junction temperature values, the actual TJ junction temperature values should be less than or equal to the requirements of the TJmax, namely TJ TJmax or less.

Attaches great importance to the degree of the thermal equilibrium speed of cooling material requirements, caused by the processing of heat of the light source can not be light attenuation. Now many manufacturers of high power LED heat sink cooling housing application using different basic aluminum alloy material, the different coefficient of thermal conductivity, heat dissipation rate of some of the material is difficult to meet the LED working conditions. Aluminum plate that cannot be ignored and thermal conductive silicone, silicone material’s thermal conductivity, using the material of actual life quality, will directly affect the work of the LED heat dissipation condition. How to reduce the intermediate links, close contact directly with the heat sink cooling effective heat dissipation of heat balance quickly, is now high quality LED lamps and lanterns is the direction of product development should be considered.