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2022-07-18 16:10:56

In terms of display technology, LCD display is a display composed of liquid crystals, and LED display is a display composed of light-emitting diodes. One pixel unit in LED digital display is led. If it is monochrome, it is generally red LED. The following editor will analyze the eight technologies of LED quality assurance with you.

To manufacture high-quality LED displays, we need to carry out technical control in the following aspects.


1. Anti static. The LED display assembly plant must take good anti-static measures. Special anti-static floors, anti-static pickaxes, anti-static mats, anti-static rings, anti-static clothes, humidity control, equipment grounding (especially footrests) are the basic requirements, and must be checked regularly with an electrometer.

2. Drive circuit design. The configuration of the driving IC of the driving substrate on the LED display module will also affect the brightness of the LED. Because the output current of the driving IC is transmitted too far on the PCB substrate, the voltage drop of the transmission line is too large, which will affect the normal working voltage of the LED, resulting in the decrease of brightness. It can be clearly seen that the brightness of the led around the LED display module is slightly lower than that in the center. Therefore, in order to ensure the uniformity of the brightness of the display, it is necessary to design the distribution diagram of the driving circuit.

3. Design current value. The nominal current of LED is 20mA, but it is generally recommended that the maximum use current be less than 80% of the nominal value. Especially for displays with small dot spacing, it is necessary to reduce the current value due to poor heat dissipation conditions. According to experience, due to the uneven attenuation speed of red, green and blue LEDs, the current value of blue and green LEDs will be reduced purposefully to maintain the uniformity of white balance after long-term use of the display screen.

LED display screen

4. Mixed lamp. The LED indicators of files with different brightness in the same color must be mixed, or plug-in according to the plug-in diagram designed according to the discrete rules to ensure the brightness uniformity of all colors on the whole screen. If there is a problem in this process, the local brightness of the display will be uneven, which will directly affect the display effect of the LED display.

5. Control the verticality of the lamp. The LED controlled by wire needs enough technology to ensure that the LED is perpendicular to the PCB substrate when passing through the furnace. The deviation of will affect the uniformity of the set led brightness, and there will be color blocks with uneven brightness.

6. The welding temperature and time of over wave tip must be strictly controlled. It is recommended that the temperature and time of wave front welding be below the preheating temperature of 1005 and the maximum of 120, and the preheating temperature rises steadily. The welding temperature is 2455 and the welding time is less than 3 seconds. After passing the furnace, please avoid vibration and impact on the LED until it returns to normal temperature. The temperature parameters of wave soldering machine must be tested regularly. This is determined by the characteristics of the LED. Overheating and fluctuating temperature will directly damage the LED, causing hidden dangers in the quality of the LED. Especially on small round and Oval LEDs like 3mm.

7. Temporary installation control. When the LED is not lit, the LED display screen is mostly caused by the dummy welding of the LED pin, the dummy welding of the IC pin, the dummy welding of the mother of the lead train, etc., and the probability of more than 50% is various types of dummy welding. The improvement of these problems needs to strictly improve the process and strengthen quality inspection. Vibration test before delivery is also a good inspection method.

8. Heat dissipation design. Because the LED will heat when working, and the high temperature will affect the attenuation speed and stability of the LED, the heat dissipation design of the PCB board and the ventilation and heat dissipation design of the shell will affect the performance of the LED.

Thank you for watching. Dylan, the manufacturer of LED display, will continue to work hard to do better!
 
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