Research And Implementation Of Static Gray Level Display On LED Screen

In recent years, LED screen has been widely used in securities and financial industry, transportation industry, advertising media industry, cultural and sports industry and so on because of its high brightness, wide viewing angle, low power consumption, long service life, quick start, high stability, low demand for environment quality and no visual fatigue. As the continuous development of LED display industry, LED screen has become a very important way for people to get all kinds of information. At the same time, the total amount of information increases rapidly. The LED screen needs to show precise content and high grayscale display is necessary. Pulse width modulation is mainly used by current LED control system to realize grayscale display. This method uses human visual inertia to achieve its goal. It changes the driving pulse width periodically. When the cycle is short enough, overall display refresh rate reached more than 60 Hz. LED display show a static image with gray scale. Because the content of LED screen is constantly refreshed, so this display method can be called dynamic grayscale display.When the LED screen implements dynamic grayscale display, what we see through the LED screen is a static image. However, each LED unit is working at a very high frequency. Generally speaking, human eye can’t perceive the constant on-off. But when we take photo of the LED screen, we can observe the flicker obviously. So we are not able to take perfect photo of grayscale LED screen. More important the constant on-off will certainly have a great impact on the life of each LED, thus leading a significant reduction in life expectancy of LED screen. In addition, the chip of each LED module have to be working to control the LED, so that the life of each chip of the LED screen will also be shortened. Above all, dynamic grayscale display will bring a variety of adverse consequences.To eliminate the negative impact of dynamic grayscale display, this paper redesigns a brave new LED module which can be used to implement static grayscale display. Besides, this paper redesigns the entire LED display gray control system, so that it can drive the brave new LED module. The specific work is as follows:1, based on consulting literature and related LED knowledge, understand the development process of LED screen and drive system, characteristics and application occasions of current LED screen. Sum up the current development situation of LED screen and drive system;2, introduce the mainly methods to achieve the grayscale display on LED screen. Introduce the working principle and flow of the pulse width modulation method used by current mainstream LED screen control system in detail;3, design a brave new LED module which can be used to implement static grayscale display. Introduce the drive chip of the new LED module and the working principle of static grayscale display;4, redesign the LED display control system, so it can drive the new LED module to implement the static grayscale display. Introduce the main components of the new control system and its software and hardware structure in detail;5, weigh the advantages and disadvantages of static grayscale display on LED screen compare to the dynamic grayscale display. Make a prospect of the future development and application.This paper verifies the capability of static grayscale display on LED screen. Through concrete experiment, it shows that the brave new LED module and LED drive control system can realize the static grayscale display on LED screen. Compare to the dynamic grayscale display, we can obviously find that the static grayscale display has a better display effect.