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Reasons and solutions for the different brightness of full-color LED display

time:2021-11-19 source:ZJ Lighting Views:192


A good LED full-color display must be adapted to different temperatures, different weathers, and can be used normally in various occasions, and it must also have a good effect for near and far light, especially for large-scale concerts. The lighting needs to be particularly good, but sometimes we find that the brightness of the LED is different. What is the reason for the inconsistent brightness of the LED full-color display? Based on years of experience, the editor has concluded the following three factors can cause the LED The brightness of the full-color display is inconsistent.

01Light-emitting element

   LED full-color display light-emitting elements, namely LED light-emitting tubes, inconsistent brightness in the production process is inevitable. However, the countermeasure adopted by LED electronic display manufacturers is to perform classification after production is completed. The smaller the brightness difference between two adjacent files, the better the consistency, but the appearance of low yield and high inventory will be more severe. Therefore, each manufacturer controls the brightness difference between two adjacent gears at 20%.

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02 drive components

   LED full-color display drive components are usually constant current drive chips, such as MBl5026 and so on. These chips include 16 constant current drive outputs, which can be used to set the current output value. The error of each output of the same chip is controlled within 3%, and the output error of different chips is controlled within 6%. It is normal for the LED full-color display to show a brightness error of 25% between pixels. If the LED tube used is not the same level and type of full-color LED display, the brightness error will rise to more than 40%.

In addition, it is worth noting that the inconsistency of the brightness of the full-color LED display is the fundamental reason for the formation of the screen. It cannot be corrected by the later proofreading equipment, as long as it is realized by the LED display manufacturer during the production and manufacturing process. Therefore, if you purchase a screen with inconsistent brightness, please contact your service provider or manufacturer to solve it.

   The display is mixed with materials during the production process, and different batches of dot matrix are used. How to solve the color difference of LED electronic display?

   Method 1

   change the current flowing through the LED, the general LED tube allows a continuous working current of about 20 mA, except for the saturation of the red LED, the brightness of the other LEDs is basically proportional to the current flowing;

  The second method

Using the visual inertia of the human eye, the pulse width modulation method is used to achieve grayscale control, that is, the light pulse width (ie duty cycle) is periodically changed, as long as the period of repeated lighting is short enough (ie the refresh frequency is high enough), The human eye does not feel that the luminous pixels are shaking. Because pulse width modulation is more suitable for digital control, today when microcomputers are commonly used to provide and LED display content, almost all LED electronic displays use pulse width modulation to control gray levels.