What factors affect LED displays the most.

LED display and other items, as in the use of this or that problem and precautions.

1, thermal design

LED work will heat up, high temperature will affect the decay rate and stability of LED, so the PCB board heat dissipation design, body ventilation heat dissipation design will affect the performance of LED.

2、Mixed light

The same colour with different brightness grade LED need to mix the light, or according to the discrete law design of the light insertion chart for the insertion of the light, in order to ensure that the whole screen the consistency of the brightness of each colour. This process, if there is a problem, there will be a large screen local brightness inconsistency, directly affecting the display effect of the LED screen.

3, design current value

LED nominal current of 20mA, generally recommended that its maximum current is not more than 80% of the nominal value, especially for point spacing is very small screen, due to poor heat dissipation conditions, should also reduce the current value. According to experience, due to the inconsistency of red, green and blue LED attenuation rate, targeted to reduce the current value of blue and green LEDs, in order to maintain the consistency of the white balance of the large screen after a long period of time.

4, drive circuit design

Large screen module on the driver circuit board driver IC layout will also affect the brightness of the LED. As the driver IC output current in the PCB board transmission distance is too far, will make the transmission path voltage drop is too large to affect the normal operating voltage of the LED resulting in a reduction in its brightness. We often find that the LED brightness around the large screen module is lower than the middle, is the reason. Therefore, to ensure that the brightness of the large screen – consistency, we must design a good distribution of drive circuits.

5, control the verticality of the light

For direct insertion of LEDs, over the furnace to have enough technology to ensure that the LED is perpendicular to the PCB board. Any deviation will affect the consistency of the brightness of the LED has been set up, the appearance of inconsistent brightness of the colour block.

6, false soldering control

LED large screen in the LED does not light up, there is often more than 50% probability for various types of virtual welding caused by, such as LED pin virtual welding, IC pin virtual welding, row pin row mother virtual welding. Improvement of these problems need to strictly improve the process and strengthen the quality inspection to solve. Vibration test before leaving the factory is also a good inspection method.

7, over the wave soldering temperature and time

Shall strictly control the wave soldering temperature and time over the furnace, it is recommended that: preheating temperature of 100 ℃ ℃ ± 5 ℃, the maximum does not exceed 120 ℃, the eye preheating temperature rise requires a smooth, welding temperature of 245 ℃ C ± 5 ℃, welding time is recommended to be no more than 3 seconds, over the furnace, do not vibrate or punch in the hit LED until the return to the state of room temperature. Wave soldering machine temperature parameters to be tested regularly, which is determined by the characteristics of the LED, overheating or fluctuating temperatures will directly damage the LED or cause LED quality hazards, especially for small sizes 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 table mat, anti-static ring, anti-static clothing, humidity control, equipment grounding (especially the foot cutter) are basic requirements, and to use static electricity meter to test regularly.