LED display brightness adjustment
The full-color LED display brightness adjustment mode has two kinds of automatic adjustment and manual adjustment. Among them, the automatic adjustment is an intelligent adjustment of the brightness according to the ambient brightness adaptive, and the manual adjustment method is realized by software. So, is it useful to use software to adjust the brightness of the display?
The current software adjusts the brightness, which is generally 256-level adjustable. In fact, the software is just an operation interface. The final change of the software operation is the PWM duty cycle of the LED display driver to achieve the change of brightness.
Two ways to control the brightness of the LED display:
One is to change the current flowing through the LED display. Generally, the current of the LED tube allows continuous operation at about 20ma. In addition to the saturation of the red LED, the brightness of other LEDs is basically proportional to the current flowing; another method is Using the visual inertia of the human eye, the pulse width modulation method is used to realize the gray scale control, that is, the optical pulse width (ie, the duty ratio) is periodically changed. As long as the refresh frequency is sufficiently high, the human eye does not feel that the illuminating pixel is jittering. . Since pulse width modulation is more suitable for digital control, in today's widespread use of microcomputers to provide LED display content, almost all LED displays use pulse width modulation to control gray levels.
At present, the brightness of the outdoor full-color LED display should be 1500 cd/m2 or more, in order to ensure the normal operation of the display, otherwise the displayed image will not be seen because the brightness is too low. However, many outdoor led display screen
s have a brightness of more than 5000 cd/m2, and the daytime playback effect is good. However, such high brightness will cause serious light pollution and cause trouble to nearby residents.
Therefore, it is very necessary to determine the brightness of the LED display. Adjusting the brightness through software is an indispensable means, and it is also a common practice in the industry. It is an effective method. After the completion of the display project, the general manufacturer will have special training for the software, the purpose is to help the customer to manage the operation as soon as possible.