Attention Points of Full Color LED Display (Part Two)

LED display like other items, inevitably encounters problems and precautions in use.

5. Mix the lamp

LEDs of the same color with different brightness levels need to be mixed, or inserted into the light pattern according to the discrete pattern to ensure the consistency of the brightness of each color of the whole LED screen. If there is a problem in this process, the local brightness of the LED display will be inconsistent, which will directly affect the display effect of the LED display.

6. Control the perpendicularity of the lamp

For DIP 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 LEDs already had been set, and the color blocks with inconsistent brightness will appear.

7. Temperature and time to pass the flow welding machine

Temperature and time to pass the flow welding machine 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. The time of welding is recommended not to exceed 3 seconds. After passed  the flow welding, 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 3mm circular and oval LEDs.

8. Control cold solder

When the LED display does not light up, there are often more than 50% probability of various types of virtual soldering, such as LED pin soldering, IC pin soldering, pin rowing and soldering. Rigorous improvements in the process and enhanced quality inspections is required in improvements in these problems. The vibration test before leaving the factory is also a good test method.