LED life, for example, to switch the the siliceous packaging materials and ceramic packaging materials, make the life of the LED’s to improve a number of white LED light spectrum contains wavelengths below 450nm short wave length light, led ceiling lamps, traditional epoxy encapsulated materials vulnerable to short wavelength light damage, led high bay, high-power white LED light to accelerate the degradation of packaging materials, according to the test results of the industry, led ceiling lamps, continuous lighting is less than one million hours of high-power white LED brightness has been reduced by more than half simply can not meet the basic requirements for lighting long life.
For the LED luminous efficiency, led ceiling lamps, improve chip package structure, can achieve the same level with the low-power white LED. The main reason is the current density increased by more than 2 times, not only does not easily removed from large chip light, the results may even lead to the dilemma of the luminous efficiency than the low-power white LED. If improving the electrode structure of the chip can theoretically solve these light extraction problem.
In order to reduce thermal resistance, led ceiling lamps, and many foreign LED manufacturers will set the LED chip surface of the radiator made of copper and ceramic materials (the heat the sink), and then using the welding and the heat of the printed circuit board with a wire connected to the use of forced air cooling fan radiator. Germany OSRAM Opto Semi conductors Gmb experimental results confirmed the structure of the LED chip can reduce the thermal impedance of the welding point of 9K / W, about 1/6 of the traditional LED LED package is applied to 2W power LED chips bonding temperature than welding points 18K, led ceiling lamps, even if the printed circuit board temperature rise to 50 ° C junction temperature at most, only about 70 ℃; led ceiling lamps, thermal impedance contrast in the past reduced the LED chip junction temperature will be a printed circuit board temperature. Therefore, it is necessary to reduce the temperature of the LED chip, in other words, reducing the LED chip to the thermal impedance of the welding point, can effectively reduce the burden of the cooling effect of the LED chip. On the other hand even if the white LED is able to inhibit the thermal impedance of the structure, led ceiling lamps, if the heat conduction from the package to the printed circuit board, the results still make light-emitting efficiency of LED temperature rise fell sharply. , Matsushita Electric Works, the development of printed circuit board and package integration technologies, the company will be 1mm square blue LED flip chip package on the ceramic substrate,led ceiling lamps, followed by and then paste the ceramic substrate in the copper printed circuit board surface, according to Panasonic reported contains the modules of the printed circuit board, including the overall thermal impedance is about 15K / W or so.