Full Color LED Display Knowledges in Common Use
1. Electrostatic prevention
Display assembly factory should have good electrostatic prevention measures. Electrostatic prevention floor, electrostatic prevention searing-iron, electrostatic prevention table pad and many other electrostatic prevention equipments are the basic requirements. In addition, regular inspection with static monitor is needed.
2. Drive circuit design
LED brightness is also affected by the distribution of drive IC on drive circuit board. As the distance output current flows through from drive IC to PCB board is too far, affecting the normal working voltage and then decreasing brightness. That why we discover that the central LEDs are brighter than the surrounding ones on the display. So good drive circuit design guarantees the brightness uniformity.3. Current value designThe normal current of LED is 20mA, generally the biggest current value we use is suggested to be less than 80% of the normal current value. Especially the display with small distance between two LEDs., as the heat dissipation is not so good, the current value should be lower. As the attenuation speeds of red, green, blue LED are different, lowering the current value of blue, green LEDs pertinently is necessary to keep the consistency.
4. Mixed lights
LEDs with same color but different brightness need to be mixed up, or plug lamp according to the discreteness rule design to make sure the brightness consistency of the whole display. If something goes wrong, the display effects will be affected directly.
5. Control verticality of the light
As for direct insertion LED, make sure the LED is perpendicular to the PCB board when passing the stove. Any deviation will led to brightness ununiformity.
6.Wave-soldering temperature and time
Wave-soldering temperature and time should be strictly controlled, suggestion: preheating temperature 100℃±5℃, not more than 120℃. Besides the preheating temperature should be stably increased. Welding temperature is 245℃±5℃, and the time is suggested to be less than 3 seconds. No vibration or impact is permitted after passing the stove till it comes back to room temperature.
7. Faulty welding control
When there is LED not emitting light, chance of faulty welding causes is 50%. Improving technics and reinforce quality inspection are needed to solve this problem. Vibration test before leaving the factory is also a good testing method.
8. Heat dissipation design
Heat is generated when LED is working, high temperature will affect the attenuation speed and stability of LED. So the heat dissipation design of PCB board, ventilation design of the box will affect the LED.