Research On White Micro-LED Array With High Power And High Modulation Bandwidth

As the fourth generation lighting source in the future, the visible light LEDs have advantage of high brightness, high electro-optical conversion efficiency, rapid modulation characteristics, reliable performance and long service life, etc. The communication technology based on visible light take advantage of LEDs'rapid modulation characteristics to achieve the transmission of message in short distance. Finally we build a system that combines lighting with communication. This system is not only save the tension spectrum-resources, but also reduces the use of communication devices. As the transmitter of visible light communication system, the characteristics of LEDs decides the data transmission speed and transmission distance. Micro-LED array are an integrated manufacturing technology of single micro-LED with size of several tens of microns, which can be used as light sources and micro-display, etc. For the purpose of improving the data transmission speed and transmission distance of visible light communication system, we will use the micro-LED array light source at transmitter. The main content of this paper is based on the micro-LED array technology to build and analysis the electrical model and optical model of LED chips for the purpose of improving the data transmission speed and transmission distance of visible light communication system.Firstly, the paper is based on the LEDs'Poisson's equation; continuity and transport equations semiconductor physics theories build the blue micro-LED electrical models. We discuss the basic equations and mathematical method of the models and analysis the characteristics of U-I, small signal AC parameters, luminous intensity and the recombination of carriers, etc. In addition, we change the size of the LED chips and analysis the influence of sizes to the LEDs'electrical properties and response speed. Finally, we draw the conclusion that the micro-LED array could improve the response speed of LED light sources. The 3dB modulation of micro-LED light sources is up to 225MHz.Furthermore, we build the Monte Carlo ray tracing optical LED models based on the theory of geometrical optics. Then we design inverted cone and inverted pyramid LED models with different inclination angles. For these two different shape models, we research the relationship between the reflective layer at the bottom as well as inclination angles and the light extraction efficiency. Meanwhile, we compare with the two different shape models'light extraction efficiency. At last, we draw the conclusion that when the inclination angle equals ten degree and the LED chip has the reflective layer, the inverted pyramid LED models'light extraction efficiency is improved at least 70%.