GaN Based Power LED Reparation And Its Characteristics

Light emitting diode as following the incandescent lamp and fluorescent lamp,the fourth generation lighting source, has the advantages of energy saving,environmental protection and long life characteristics. From the initial lighting fields such as landscape lighting and traffic lights, it begins to be used as the computer,television and other large size LCD backlight, so it has become an indispensable key component of the modern information society. It is gradually used in some new developed fields such as agriculture and medicine. GAN based LED is developing fast in its quality in recent years, and there has been a lot of new LED. This paper is supported by the National High Technology Research and Development Program(863 program) Funded Projects(No. 2009AA03A1A3) and National Key Technologies R&D Program(No. 2011BAE01B14). The main contents of the study are as follow:Firstly, study and analysis of the key technology of GAN based high voltage LED. Specific analysis of the impact factors of deep groove etching ICP; analysis of the different mask effect on deep trough level morphology; analysis of the impact of ITO corrosion which is not clean to ICP etching, and the effect on LED devices;analysis of the effect of different electrode materials and the structure of LED devices.Secondly, 12 V blue light high voltage LED was made to accept experiments in different temperatures from 25℃-60℃, results show that the luminous flux of the blue chip falls as the temperature rises. With the increase of temperature, the forward voltage decreases, the luminous efficiency increases. It shows that Auger recombination is not the main reason resulting in the GaN based LED optical attenuation, the temperature changes have different influences on different materials.Thirdly, 12 V GaN based high-voltage green LED was prepared, and the human body goes through a series of reverse electrostatic blow after the model test and variable current test. After the attack, LED samples almost lost the PN junction characteristic. It is concluded that the effect of electrostatic blow on the high voltage LED GaN effect is the same with normal LED device.Fourthly,four LED of different color temperature of 2700 k, 3000 k, 4000 k and5500k go through an current experiment of 25-900 mA, with the injection current increased, the rate of rise of the luminous flux of LED gradually decreased,photosynthetic efficiency increased at first and then decreased rapidly, which is due to electron overflow from the localized states in the non radiative recombination; colorrendering index rose 30%-35%,Blue ray radiation increased, a drop in conversion efficiency of phosphor. It is observed in the short wavelength range of peak wavelength blue shift, which is due to the quantum confined Stark effectFinally, select both A and B companies’ s 1 w white light samples and b company’s blue power LED for 1 w, 350 ma, temperature of 35 degrees long aging test for 2250 h. Luminous flux and photosynthetic efficiency of LED samples are trend to decay, although the decline degree is different, the overall trend is the same.All voltage devices have increased over time slightly upward trend, and forward voltage rise will appear color distortion, thus will produce off color, in order to achieve the purpose of improving energy efficiency and saving,we should consider the effect of low environmental temperature on the LED, in accordance with the actual requirements to choose different parameters of the LED.