A good full-color LED display must be able to adapt to different temperatures and weather, and be able to be used normally in many occasions. In addition, it needs to have a good effect on far and near light, especially for large-scale concerts. The special effects of lighting must be particularly good. However, based on years of experience, Winbond Ying Optoelectronics has summarized the following three factors, which will lead to uneven brightness of the full-color LED display.
1. Optical components
As the light-emitting element of the full-color LED display, the LED light-emitting tube inevitably has the problem of inconsistent brightness during the production process. The countermeasure adopted by full-color LED display manufacturers is to divide the stage after the product is produced. The brightness difference of the two adjacent stages is small, and the consistency is better, but the yield and inventory are higher. Therefore, every full-color LED display manufacturer controls the difference in brightness between two adjacent levels at about 20%.
2. Drive components
The driving component of full-color LED display usually adopts constant current driving chip, such as MBl5026. It includes 16 constant current drive outputs, and the current output value can be set by resistance. The output error of each chip is controlled within 3%, and the output error of different chips is controlled within 6%. Under normal circumstances, on a full-color LED display, a 25% brightness error is displayed between each pixel. If the LED tube used is not a full-color LED display of the same specification and model, the brightness error will rise to more than 40%.
In addition, the inconsistency of the brightness of the full-color LED display is the root cause of the formation of the flower screen. The post-correction device cannot be used for correction, but it is realized in the production process of the full-color LED display manufacturer. So, if you buy a full-color led display with inconsistent picture brightness, please contact the manufacturer of the full-color led display.
Full color LED display
In the production of full-color LED display, materials are mixed and different batches of grids are used. How to solve the problem of color difference of full-color LED display?
method 1:
When the current flows through the LED, the LED tube usually allows a continuous working current of about 20 mA. Except for the saturation of the red LED, the brightness of the other LEDs is almost proportional to the current passed.
Method 2:
Using human visual inertia, grayscale control is achieved by changing the light pulse width (duty cycle) regularly. If the period of repeated lighting is short enough (that is, the refresh rate is high enough), the human eye's luminous pixels are suitable for digital control. Therefore, in today's use of microcomputers to provide LED display content, most full-color LED displays use pulse width to control grayscale.
