LED electronic display screen is an electronic display, which is combined with computer technology, information processing technology, electronic technology, phonology, chromatics and other high and new technologies. The LED display screen can be divided into monochrome screen, double color screen and full color display. As the name implies, the monochrome screen is composed of a single color of LED (see figure 1). A pixel display which is in the red and green LED is called double color screen or color screen (see figure 2). And a pixel display consists of the red, green and blue LED is called the tri color screen or full color screen(see figure 3).
Full color display of LED screen can be divided into indoor and outdoor screens. In general, there are two driving methods, one is the change of current LED whose operating current had better be set below 20mA, and the other one is that using human visual inert, gray control can be realized with pulse modulation. People’s feeling about the average brightness of pixel depends on its duty ratio, which can change periodically. As long as the cycle is short enough, human eyes will not feel its duty ratio.
With the improvement of green chip brightness and the drop in price, the full color display is being popularized and promoted at unprecedented speed. Especially, the appeal of Beijing "Green Olympics" makes market prospects of the full color LED display more and more attractive. With the development of more than ten years, the progress of domestic display manufacturers is very fast. However, compared with the developed countries of Europe, America and Japan, there is still a certain gap, especially in the packaging technology of LED display devices and design level.
