Why does LED full color display screen have color difference?

Outdoor LED full-color display brightness inconsistency is what causes it? Summarized the following three factors can lead to LED full color display brightness inconsistency.

1.Light-emitting elements

LED full-color display light-emitting components that LED light-emitting tube, in the production process, brightness inconsistency is inevitable. But the countermeasure adopted by the LED electronic screen manufacturers is to file after the completion of production, the smaller the difference between the brightness of the two neighboring files, the better the consistency, but will form a low yield and high inventory of the more serious appearance.

Lamp beads as the core components of the LED display, the color difference problem arises mainly from the following factors:

① Poor heat dissipation design, resulting in high LED temperature, affecting color performance.

② Phosphor coating is not uniform, the color temperature of the thick part of the coating is low and yellowing phenomenon occurs.

③ The quality of phosphor varies, affecting the display effect.

④ Improper ratio of adhesive powder, resulting in impaired display effect.

 In response to the above problems, we propose the following solutions:

① Optimized heat dissipation design ensures stable temperature of LED display in the working process and reduces color difference.

② Adopt advanced phosphor preparation technology to ensure uniform coating and improve color consistency.

③ Select high-quality phosphor of well-known brands and conduct several sample comparison tests before mass production.

④ Strictly control the curing temperature and time of AB adhesive to avoid the yellowing phenomenon caused by long time high temperature baking.

2. Drive components

LED full-color display driver components are usually constant-current driver chips, such as MB15026. These chips include 16 internal constant current driver outputs, you can use the resistor to set the current output value, the same chip each output error control within 3%, not the same chip output error control within 6%. 25% brightness error between the pixels of the LED full-color screen is normal, for example, the use of the LED light-emitting diode is not the same level of the type of full-color LED display, it will make the brightness difference rises to more than 40%.

It is also worth noting that the full-color LED display brightness inconsistency, is an important reason for the formation of the flower screen, cannot be corrected with the later proofreading equipment, only by the LED screen manufacturers production and manufacturing process to achieve. So buy to the brightness inconsistent screen, please contact your service provider goods manufacturers to seek a solution.

3. The display was mixed during the production process, using different batches of dots.

How to solve the LED display color is not the same?

The first method: is to change the power supply flowing through the LED, the general LED tube allows continuous operation current in about 20 mA, in addition to the red LED saturation phenomenon, the other LED brightness is basically proportional to the current flowing through.

The second method: the use of the human eye's visual inertia, with pulse width modulation method to achieve gray scale control, that is, periodically change the width of the light pulse (i.e., duty cycle), as long as this repeated lighting cycle is short enough (i.e., refresh frequency is high enough), the human eye is not felt by the light-emitting pixel jitter. Because pulse width modulation is more suitable for digital control, so in the universal use of microcomputer to provide LED display content today, almost all of the LED electronic display screen is to use pulse width modulation to control the level of gray scale.