The gray level of LED electronic screen industry can also be called LED brightness. Gray level, also known as central color, is mainly used to transmit pictures, pictures, video screens and parting. There are three methods of 16 levels, 32 levels and 64 levels. It uses matrix processing method to process the pixels of files into 16, 32 and 64 levels to make the transmitted pictures clearer. Whether it is a full-color screen or a two-color screen, in order to display pictures or animations, it is necessary to adjust the brightness of each LED that constitutes the pixel. The precision of the conditioning is what we generally call the gray level.
1、 Change the current flow.
2、 Pulse width modulation:
1) Change the current flowing through the LED. Generally, the LED tube allows continuous operation with a current of about 20 mA. In addition to the full scene of red LED, other LED grayscale is basically related to the current component;
2) Using the lazy vision of the human eye, the pulse width modulation method is used to complete the grayscale control, that is, periodically changing the light pulse width (i.e., the duty cycle). As long as the period of the repeated lighting is short (that is, the rewriting frequency is satisfied with high), the human eye can not feel the flicker of the luminous pixels. Because PWM is more suitable for digital control
Therefore, in today’s widely used microcomputer to provide LED display content, almost all LED electronic screens use pulse width modulation to control the gray level. LED control system is generally composed of main control box, scanning board and display and control equipment.
