LED screen rental screen and other items, it is inevitable to encounter this or that kind of questions and precautions in the use. In the use of full-color LED display screen rental time, may be because of the eight questions, resulting in difficult or affect the use of large screen, and can extend its service life.
1. Thermal planning
When LED works, it will generate heat. If the temperature is too high, it will affect the attenuation speed and stability of LED. Therefore, the heat dissipation planning of PCB board and the ventilation and heat dissipation planning of box will affect the performance of LED.
2. Mixed lamp
Led with different brightness of the same color needs to mix lights, or plug lights according to the discrete rule planning to ensure the consistency of brightness of each color in the whole screen. If there is doubt in this process, the brightness of large screen will be inconsistent, which will directly affect the display function of LED screen.
3. Planning current value
The nominal current of LED is 20mA, and it is generally advocated that the maximum applied current should not exceed 80% of the nominal value, especially for the large screen with small distance between points, because of the poor heat dissipation condition, the current value should be reduced. According to experience, due to the inconsistency of attenuation speed of red, green and blue LEDs, it is necessary to reduce the current value of blue and green LEDs to maintain the consistency of white balance after long-term use of large screen.
4. Drive circuit planning
The layout of driver IC on the large screen module will also affect the brightness of LED. The over-current of the LED on the PCB transmission path will affect the normal output voltage. We often find that the LED brightness near the large screen module is lower than that in the middle, which is the factor. Therefore, to ensure the consistency of the brightness of the large screen, it is necessary to plan the distribution of the driving circuit.
5. Control the verticality of the lamp
As for the direct plug-in led, the technology should be satisfied when passing through the furnace to ensure that the LED is perpendicular to the PCB board. Any deviation will affect the brightness consistency of the LED which has been set, showing the color block with inconsistent brightness.
6. Virtual welding control
When the LED is not on, there is often a more than 50% probability that it is caused by various types of false soldering, such as LED pin false soldering, IC pin false soldering, pin and bus false soldering, etc. The improvement of these questions needs to strictly improve the technology and strengthen the quality inspection to deal with. The oscillation test before leaving the factory is also a good test method.
7. Temperature and time of over wave soldering
The temperature and time of wave front welding should be strictly controlled. It is advocated that the preheating temperature should be 100 ℃± 5 ℃, the maximum temperature should not exceed 120 ℃, and the preheating temperature should rise steadily. The welding temperature should be 245 ℃± 5 ℃, and the welding time should not exceed 3 seconds. After passing the furnace, do not oscillate or impact the LED until it recovers to normal temperature. The temperature parameters of wave soldering machine should be checked regularly, which is determined by the characteristics of LED. Overheating or shaking temperature will directly damage led or cause led quality risk, especially for small-scale round and Oval LEDs such as 3mm.
8. Antistatic
LED display rental screen assembly plant should have good anti-static methods. Special anti-static ground, anti-static floor, anti-static soldering iron, anti-static pad, anti-static ring, anti-static clothing, humidity control, equipment grounding (especially foot cutting machine) are all basic requirements, and they should be checked regularly with an electrostatic meter.