The color LED large screen is composed of several RGB lamp beads. Its light-emitting principle is mainly from the supply of power supply current and the supply of control chip signals to realize the wonderful display of the LED large screen. At present, the color LED large screen is developing towards high density, and its display effect is more delicate and realistic. The current software adjusts the brightness, generally in a 256-level adjustable way.
In fact, the software is just an operation interface. What is finally changed through the operation of the software is the PWM duty cycle of the LED large screen driver to realize the change of brightness. Familiar people know that there are two ways to adjust the brightness of the color LED large screen, automatic adjustment and manual adjustment. Among them, the automatic adjustment is an intelligent adjustment method based on the environment brightness, and the manual adjustment method is realized through software. Then let's see if it is useful to use software to adjust the brightness of the large screen? Two methods of controlling the brightness of the LED large screen: Currently The brightness of the outdoor color LED large screen must be above 1500cd/m2 to ensure the normal operation of the large screen, otherwise the displayed image cannot be seen clearly because the brightness is too low.
But at present, the brightness of many outdoor LED large screens exceeds 5000cd/m2, and the playback effect is good during the day, but such high brightness at night will cause serious light pollution, causing troubles to nearby residents. One is to change the current flowing through the large LED screen. Generally, the LED tube allows a continuous working current of about 20ma. Except for the saturation phenomenon of the red LED, the brightness of other LEDs is basically proportional to the current flowing; the other method is Using the visual inertia of the human eye, the pulse width modulation method is used to achieve grayscale control, that is, to periodically change the light pulse width (that is, the duty cycle). As long as the refresh rate is high enough, the human eye cannot feel the jitter of the luminous pixels . Since pulse width modulation is more suitable for digital control, today when microcomputers are commonly used to provide LED display content, almost all large LED screens use pulse width modulation to control gray levels.
Therefore, it is very necessary to determine the brightness of the LED large screen. Adjusting the brightness through software is a necessary means, and it is also a common practice in the industry. It is an effective method. Generally, after the LED large screen project is completed, the manufacturer will have special training for the software, the purpose is to help customers get started with management operations as soon as possible. .