The led display is the same as other items, and it is inevitable to encounter such problems or precautions during use. When using the full-color led large screen, there may be eight problems that cause difficulties or affect the use of the large screen and extend its life.
1 , heat dissipation design
When the LED works, it will generate heat. If the temperature is too high, it will affect the attenuation speed and stability of the LED . Therefore , the heat dissipation design of the PCB board and the ventilation and heat dissipation design of the cabinet will affect the performance of the LED .
2 , mixed lights
LEDs of the same color with different brightness levels need to be mixed with lights, or inserted into the light pattern according to the discrete pattern to ensure the consistency of the brightness of each color of the whole screen. If there is a problem in this process, there will be a phenomenon that the local brightness of the large screen is inconsistent, which directly affects the display effect of the large screen of the led .
3 , design current value
The nominal current of the LED is 20mA . It is generally recommended that the maximum current used is not more than 80% of the nominal value . Especially for large screens with small dot spacing, the current value should be reduced due to poor heat dissipation conditions. According to experience, due to the inconsistency of the red, green and blue LED attenuation speeds, the current values ​​of the blue and green LEDs are purposely reduced to maintain the consistency of the white balance after long-term use of the large screen.
4 , drive circuit design
The arrangement of the driver board driver IC on the large screen module also affects the brightness of the LED . Since the driving IC output current is too far away on the PCB , the voltage drop of the transmission path is too large, which affects the normal operating voltage of the LED and causes its brightness to decrease. We often find that the brightness of the LEDs around the large screen module is lower than the middle, which is why. Therefore, to ensure the consistency of the brightness of the large screen, it is necessary to design the drive circuit distribution map.
5 , control the verticality of the lamp
For in- line LEDs , there must be enough process technology to ensure that the LEDs are perpendicular to the PCB . Any deviation will affect the brightness consistency of the already set LEDs , and the color blocks with inconsistent brightness will appear.
6 , virtual welding control
led curtain in case of a large screen LED is not lit, often more than 50% probability of the various types of Weld caused, such as LED pin Weld, IC leads Weld, Pai Pai mother Weld like. Improvements in these problems require rigorous improvements in the process and enhanced quality inspections. The vibration test before leaving the factory is also a good test method.
7 , over wave soldering temperature and time
The temperature of the wave front welding and the furnace time must be strictly controlled. The recommended temperature is: preheating temperature 100 °C ± 5 °C , maximum not exceeding 120 °C , and the preheating temperature rise is required to be stable, the welding temperature is 245 °C ± 5 °C , welding The time is recommended not to exceed 3 seconds. After the furnace is over, avoid vibrating or impacting the LED until it returns to normal temperature. The temperature parameters of the wave soldering machine should be checked regularly, which is determined by the characteristics of the LED . The overheated or fluctuating temperature will directly damage the LED or cause LED quality hazard, especially for small and oval LEDs with small dimensions such as 3mm .
8 , anti-static
Led large screen assembly factory should have good anti-static measures. Special anti-static grounding, anti-static floor, anti-static soldering iron, anti-static mat, anti-static ring, anti-static clothing, humidity control, equipment grounding ( especially cutting machine ) are basic requirements, and should be regularly tested by static electricity meter. .
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