Knowledge: 8 factors that affect LED displays(part 2)

4. Drive circuit design

LED digital display exporter shares that the layout of the drive circuit board on the large screen module will also affect the LED brightness. Because the drive IC output current travels too far on the PCB board, the voltage drop in the transmission path will be too large, which will affect the normal working voltage of the LED and reduce its brightness. We often find that the LED brightness around the large screen module is lower than the center, which is the reason. Therefore, to ensure the consistency of the brightness of the large screen, it is necessary to design a good drive circuit distribution diagram.

5. Control the verticality of the light

For the straight plug LED, there should be enough technology to ensure that the LED is perpendicular to the PCB board when passing through the furnace. Any deviation will affect the already set LED brightness consistency, brightness inconsistent color block.

6. Virtual welding control

When LED big screen is not bright, there is often more than 50% probability for various types of virtual welding, such as LED pin virtual welding, IC pin virtual welding, row pin virtual welding and so on. The improvement of these problems requires strict process improvement and quality inspection. Vibration test before delivery is also a good test method.

7. Wave soldering temperature and time

Must strictly control the wave crest welding temperature and furnace time, recommended for: preheat temperature 100 ℃ + / - 5 ℃, the highest do not exceed 120 ℃, and the requirement of preheating temperature increasing is smooth, the welding temperature is 245 ℃ + 5 ℃, welding time suggest no more than 3 seconds, after furnace vibration or shock LED of avoid by all means, until the normal temperature state. Wave soldering machine temperature parameters to be regularly tested, which is determined by the characteristics of the LED, overheating or fluctuating temperature will directly damage the LED or cause LED quality problems, especially for small size such as 3mm round and oval LED.

8. Anti-static

LED large screen assembly plant should have good anti - static measures. Special anti-static ground, anti-static floor, anti-static soldering iron, anti-static radio pad, anti-static ring, anti-static clothes, humidity control, equipment grounding (especially cutting machine) are basic requirements, and to use the electrostatic instrument regularly tested.