Analysis And Simulation Of GAN - Based Light - Emitting Diode Light Out

With the unique advantages, LEDs are widely used in displays, traffic signals and optical communications etc. With the white high-brightness LEDs developing,LEDs are considered to be green light source for general lighting. Compared with traditional light source,there are many advantages in LEDs such as energy-saving,environmental protection, high reliability, high efficency, long life, etc. In recent years, LED lighting gradually go into our lives. When flashlight, table lamp has spread to ordinary households, the car headlights, street lamps and indoor lighting are beginning to enter the market. The development of LED lighting is blocked by the high cost and the low luminescence efficiency. Currently, the chip of LEDs has high internal quantum efficiency. For improving the luminous efficiency, the key problem is that how to improve light extraction efficiency. So to find some ways to increase the light extraction efficiency become a research hotspot.Improving light extraction efficiency needs to re-design or optimize the chip and the package optical structure. For reducing development costs and shortening the development cycle,the theoretical analysis or computer analysis method is the key. There are many analytical methods, including the transfer matrix method, finite difference time-domain method, finite element method and ray-tracing method, etc. Several methods of computer analysis model were established. One of them which based on ray-tracing Monte Carlo simulation provides a good method to optimize the design of LED optical structure. Based on discussing Snell law and Fresnel's law on affecting the basic factors of light extaction of LEDs, a new computer simulation process of light extracton of LEDs based on Monte Carlo method is proposed. The proposed method performs well in the simulation efficiency and the accuracy.For the method of improving light extraction efficiency, the refractive index of package and new strcture models are simulated by the proposed method based Monte Carlo simulation. Simulation results show that high refractive index coating material and the new structure will improve the light extraction efficicency of the most of LEDs'structure. The reflected spectra of GaN-based DBR for blue LED at 460 nm are studied by transfer matrix method. Many factors are described quantitatively such as the incident medium, the incident angle, blue shift of wavelength, etc. Several wide-angle of DBR construction program proposed and analyzed. The results show Coupled DBR increasing wide-angle reflection at the cost of reduce reflectivity or doubled the thickness of films. In addition, the micro-structure to improving the light extraction efficiency is analyzed by ray-tracing method. A number of parameters of the best micro-strcture are identified.