Those things about LED display brightness adjustment

Familiar people know that there are two ways to adjust the brightness of the full-color LED display: automatic adjustment and manual adjustment. Among them, the automatic adjustment is an intelligent brightness adjustment method that is adaptive according to the ambient brightness, and the manual adjustment method is implemented by software. So let ’s take a look at the software to adjust the brightness of the display screen.

The current software adjusts the brightness, which is generally 256 levels adjustable. In fact, the software is only an operation interface, and the PWM duty cycle of the LED display driver is finally changed through the operation of the software to achieve the change in brightness.

Two methods to control the brightness of the LED display:

One is to change the current flowing through the LED display. Generally, the current allowed by the LED tube to work continuously is about 20ma. Except for the red LED which is saturated, the brightness of other LEDs is basically proportional to the current flowing; the other method is Utilizing the visual inertia of the human eye, using pulse width modulation to achieve grayscale control, that is, periodically changing the light pulse width (ie, the duty cycle), as long as the refresh frequency is not high enough, the human eye cannot feel the light emitting pixels in shake. Since pulse width modulation is more suitable for digital control, today, with microcomputers commonly used to provide LED display content, almost all LED displays use pulse width modulation to control gray levels.

At present, the brightness of outdoor full-color LED display screens must be above 1500cd / m2 to ensure the normal operation of the display screen, otherwise the displayed image will not be clear because the brightness is too low. However, the brightness of many outdoor LED displays currently exceeds 5000cd / m2, and the playback effect is good during the day. However, such high brightness at night will cause serious light pollution and cause distress to nearby residents.

Therefore, it is very useful to determine the brightness of the LED display screen. Adjusting the brightness through software is a basic method and a common practice in the industry. It is an effective method. Generally, after the display project is completed, manufacturers will have special training for the software to help customers get started with management operations as soon as possible.