With global energy shortage and environmental pollution, the LED with its energy-saving and environmental features of the vast space, the application of LED light products are attracting the world's attention in the lighting field. In general, the LED lights work stability, no matter the quality is good or bad, and the lamp cooling is essential, the heat of the high brightness LED lamps (t8 led fluorescent tube) on the market, often using the natural cooling effect, which is not satisfactory. LED lamps, LED light source to create LEDs, thermal structure, drives, lens, so the heat is also an important part, if the LED can not be a good heat, it's life will also be affected.
1, thermal management is the main problem in the high-brightness LED applications
P-type doping of III-nitride limited by the solubility of the Lord and hole higher than that of Mg activation energy and heat are particularly vulnerable in the p-type region; Sapphire substrates is extremely low thermal conductivity of the device thermal resistance increase, resulting in severe self-heating effect, have a devastating impact on device performance and reliability.
2, the heat of high-brightness LED
Heat concentrated in a small size chip, the chip temperature rises, causing non-uniform distribution of heat stress, decline in the luminous efficiency and the lasing efficiency of the phosphor; the device failure rate increased exponentially when the temperature exceeds a certain value. The statistics show that the component temperature rise of 2 ° C, reliability decreased by 10%. When multiple LEDs (t8 led fluorescent tube) are densely packed composition of white light illumination system, the heat dissipation problem is more serious. Solve the problem of thermal management has become a prerequisite for high-brightness LED Street Light applications.
3, the chip size and the cooling of relations
The most direct way to improve the brightness of power LED (t8 led fluorescent tube) is to increase the input power is bound to increase the input power in order to prevent saturation of the active layer must increase the size of the pn junction. Single-tube power increases depends on the device the ability to export heat from the pn junction to maintain the existing chip material, structure, packaging technology, the current density on the chip the same and equivalent thermal conditions, a separate increase the size of the chip junction area The temperature will continue to rise.