LED the heat dissipation

LED the heat dissipation has become more and more attention by people, this is because the LED light failure or its life is directly related to its junction temperature, heat dissipation is bad junction temperature is high, service life is short, according to the ray news law temperature for every 10 ℃ below 2 times longer life. Released from the Cree company droop and junction temperature diagram ( FIG. 1) You can see in, if the junction temperature can control at 65 ° C, then the droop of 70% in life can be as high as 100000 hours! This is the dream of life, but really can achieve? Yes, as long as able to deal with it seriously heat dissipation problems are likely to do it! Unfortunately, now the actual leds heat dissipation and the different! So that the service life of LED lamps and lanterns has become a the main problems affecting its performance, therefore must be taken seriously!

in figure 1. Droop and the relationship between the junction temperature and junction temperature affects not only long life, also directly affect the luminous efficiency for a short period of time, such as Cree XLamp7090XR - for the company E amount of light and the relationship between the junction temperature is shown in figure 2.

in figure 2. Relationship and mild glow if at junction temperature is 25 degrees when light is 100%, then the junction temperature rise to 60 degrees, the count was only 90%; Junction temperature is 100 degrees when it fell to 80%; 140 degrees is only 70%. Visible to improve heat dissipation, junction temperature control is very important thing. In addition to the LED fever will make the spectrum of mobile; High colour temperature rise; Forward current increases, When the power is constant voltage ； Reverse current also increases; The thermal stress increases; Phosphor accelerated aging of epoxy resin and so on all sorts of problems, so the LED heat dissipation is one of the most important in the design of LED lamps and lanterns.