LED display technical control
With its own excellent characteristics and the promotion of the market, the LED display has now been successfully transformed from the traditional bulky color single type to the light and easy-to-install, multi-functional full-color LED display, color screen LED display, LED rental screen, LED stadium screen, floor tile LED display has gradually become the mainstream products in the market, and won the favor of users. It is enough to show the huge use of LED display screens, especially with the gradual development of LED display screens, large-scale LED display screens can be seen in almost every corner of the world, which in general adds color to the world and beautifies every City. At the same time, it has been well received by consumers. The LED display industry has developed rapidly and has formed a new stage of development. Specifically divided into 3 stages:
1. LED display utility model stage: LED display has the characteristics of environmental protection, high brightness, high definition, high reliability and other characteristics gradually highlighted, and in the previous stage, the LED display market only met people’s needs, but in the LED display The screen products do not meet the requirements, and the quality is not enough. With the development of LED display, now LED products have a new breakthrough. At least an improvement over the previous stage. A series of products that are completely different from traditional light source applications have also been developed. There will be a larger and broader development space for LED displays.
2. LED display intelligent control stage: With the continuous progress and development of LED display technology, LED, as a semiconductor industry, will also take this high-speed train to play its high controllability characteristics. From homes to office buildings, from roads to tunnels, from cars to walks, from indoors to outdoors, LED display systems with intelligent control will bring higher-level services to human beings. The LED display industry will also go from making products to designing products to providing overall solutions.
3. LED display replacement acceptance stage: Since the characteristics of LED display products are mainly reflected in the characteristics of high luminous efficiency (low energy consumption) and long life, this stage is the early stage of LED display development. There seems to be some comparison. Of course, customers have a process of acceptance, and customers have a transition and acceptance in terms of usage habits and appearance. Let customers understand the characteristics of LED display products, and choose one with the characteristics of power saving and longevity. In this way, customers can easily accept its relatively high price, especially in commercial occasions, not to mention that customers are second in price, mainly in terms of quality.
Do a good job in 8 major technical control to ensure the quality of LED display
The love of the majority of users is definitely inseparable from the quality of the product. To produce a high-quality LED display, LED display manufacturers have concluded that they need to do technical control in the following aspects:
1. Anti-static LED display electronic display assembly factories should have good anti-static measures. Special anti-static ground, anti-static floor, anti-static soldering iron, anti-static table pad, anti-static ring, anti-static clothing, humidity control, equipment grounding (especially the foot cutter) are all basic requirements, and should be checked regularly with an electrostatic meter .
2. Drive circuit design The arrangement of the drive IC on the drive circuit board on the LED display module will also affect the brightness of the LED. Since the transmission distance of the output current of the driver IC on the PCB is too long, the voltage drop in the transmission path will be too large, which will affect the normal operating voltage of the LED and reduce its brightness. We often find that the LED brightness around the LED display module is lower than that in the middle, which is the reason. Therefore, in order to ensure the consistency of the brightness of the display screen, it is necessary to design the distribution diagram of the driving circuit.
3. Design current value The nominal current of the LED is 20mA. It is generally recommended that the maximum use current should not exceed 80% of the nominal value. Especially for the display screen with small dot spacing, the current value should be reduced due to poor heat dissipation conditions. . According to experience, due to the inconsistency of the attenuation speed of red, green and blue LEDs, the current values of blue and green LEDs are reduced in a targeted manner to maintain the consistency of the white balance of the display screen after long-term use.
4. Mixed lights LEDs of the same color with different brightness levels need to be mixed with lights, or inserted according to the light-insertion diagram designed by the discrete law to ensure the consistency of the brightness of each color on the entire screen. If there is a problem in this process, the local brightness of the display screen will be inconsistent, which will directly affect the display effect of the LED display.
5. Control the verticality of the light. For in-line LEDs, there must be enough process technology to ensure that the LEDs are perpendicular to the PCB board when passing through the furnace. Any deviation will affect the brightness consistency of the LEDs that have been set, and color blocks with inconsistent brightness will appear.
6. The temperature and time of wave soldering must be strictly controlled. The temperature and time of wave soldering must be strictly controlled. It is recommended that the preheating temperature be 100°C ± 5°C, and the maximum temperature should not exceed 120°C. The temperature is 245℃±5℃, and the welding time is recommended not to exceed 3 seconds. Do not vibrate or impact the LED after passing through the furnace until it returns to normal temperature. The temperature parameters of the wave soldering machine should be checked regularly, which is determined by the characteristics of the LED. Overheating or fluctuating temperature will directly damage the LED or cause hidden dangers to the quality of the LED, especially for small size such as 3mm round and oval LEDs.
7. When the LED display is not lit, there is often more than 50% probability that it is caused by various types of virtual welding, such as LED pin virtual welding, IC pin virtual welding, and pin header and mother virtual welding. Wait. The improvement of these problems needs to strictly improve the process and strengthen the quality inspection to solve. The vibration test before leaving the factory is also a good inspection method.
8. Heat dissipation design LED will generate heat when working, and if the temperature is too high, it will affect the attenuation speed and stability of the LED. Therefore, the heat dissipation design of the PCB board and the ventilation and heat dissipation design of the box will affect the performance of the LED.
LED display is in a stage of rapid development and growth. It is believed that in the near future, LED display will be used in more fields, and various new products of LED display will emerge in the market.