After several years of development, LED screens seem to have become a mature industry at first glance. In fact, both domestic and foreign manufacturers still have a long way to go, especially outdoor large screens. After two years of operation, most products are very It is difficult to maintain within user expectations.
How to choose LED display screen? It’s important to get rid of misunderstandings!
1. First of all, there is a big misunderstanding. Most people think that the main materials of the screen, LED and IC, have a life span of 100,000 hours. They operate 24 hours a day, 365 days a year, and have a service life of more than 11 years. Therefore, most customers Only care about using well-known LEDs and ICs. In fact, these two are only necessary conditions, not sufficient conditions, because the reasonable use of red, green, and blue lamps is more important for the display screen. For lamps of different colors, it is necessary to make them work in the best condition. For a A good display will be even more important. Reasonable adjustment of IC can also help overcome unreasonable wiring problems of PCB. Just like a car with a good engine and circuit control, it may not necessarily become a good car. The key factors here are as follows:
Since LEDs and ICs are semiconductor devices, they are picky about the environmental conditions of use. It is best to operate at room temperature of around 25°C for their best working mechanism. But in fact, a large outdoor screen will be used in different temperature environments, which may be above 60°C in summer and below -20°C in winter. When manufacturers produce products, they use 25°C as the test condition and classify different products into different grades. However, the actual operating conditions are 60°C or -20°C. At this time, the working efficiency and performance of LEDs and ICs are inconsistent, and they may originally belong to the first grade. There will be multiple levels, the brightness will be inconsistent, and the screen will naturally become blurry.
This is because under different temperature conditions, the brightness attenuation and decrease of the three colors of red, green, and blue lights are different. At 25°C, the white balance is normal, but at 60°C, the three colors of LEDs The brightness of the screen has decreased, and its attenuation values are inconsistent, so the brightness of the entire screen will decrease and the color cast will occur, and the quality of the entire screen will decrease. What about IC? The operating temperature range of IC is -40℃-85℃. The temperature inside the box will rise due to excessive external temperature. If the temperature inside the box exceeds 85°C, the IC will work unstable due to the high temperature, or the temperature drift will cause the current between channels or the difference between chips to be too large. Causes flower screen.
2. Power supply is also very important. Since the working stability, output voltage value and load capacity of the power supply will be different under different temperature conditions, since it plays a role in logistics support, its support capabilities directly affect the quality of the screen.
3. The cabinet design is also very important for the display screen. On the one hand, it has a circuit protection function, on the other hand, it has a safety function, and it also has dust-proof and waterproof functions. But what is more important is whether the ventilation and heat dissipation thermal circuit system is well designed. As the boot time increases and the outside temperature increases, the thermal drift of the components will also increase, resulting in poor image quality.
The above factors are all interrelated and will affect the quality and life of the display. Therefore, when customers choose a screen, they must conduct a comprehensive observation and analysis to make a correct judgment.
The impact of temperature on large screens is not just that. Suppose the customer purchases a large screen that is 10 meters wide and 6 meters high (60 square meters). Although the total area is not large, the internal components are each unit box, and the space between each unit box is The temperature is not necessarily balanced, and the temperature inside the box will also be affected by air convection and the temperature will be inconsistent, resulting in different temperatures between unit boxes or inside the unit box, resulting in inconsistent working efficiency of the semiconductor device, which is manifested in the luminescence of the LED lamp. The brightness is inconsistent and the screen looks “flowery”. Don’t underestimate the outdoor temperature. Just think about the example of hard-boiled eggs in a car in summer. What’s more, the LED display screen still needs to emit light even under summer exposure. (The light emitted must be stronger than sunlight to be effective), and its light will definitely generate heat. These are all influencing factors.
It is not only fragile LEDs, ICs and other semiconductor devices that struggle with hot and cold temperatures, but also sturdy ABS, masks, iron boxes, connectors, and various solder joints. Masks get wet under sunlight and after low-temperature and freezing rain. Under the multiple attacks of air, some deformations and warping angles of up to 2-3 mm are produced. In addition, ultraviolet irradiation also causes the color of the mask panel to change. In this way, under various climate changes throughout the year, the mask panel itself seen by the audience will change color. Patches and deformation will block the light-emitting angle of the fluorescent tube and create dark areas; deformation will also affect the curvature of the PCB board, resulting in unreliable solder joints, resulting in false soldering, causing the LED to turn on and off. Moreover, due to the moisture and oxidation of the air, the oxidation contact surface of the connector is reduced, and coupled with the subtle effects of vibration and deformation, the micron-level coating of the connector does not form a tight contact, resulting in signal or power interruption and large screen failure.
Deformation and mechanical fatigue will also affect the iron box and outer frame, causing the screen to be uneven, the module and the iron box not to fit tightly, partial leakage and other consequences.
Therefore, to choose a good large screen, the first line must be to choose a good lamp, which is durable and adaptable, and the assessment of other materials and processes must not be underestimated. Just like a car, a repair shop with several people can also put it together. A factory with tens of thousands of people is also assembling a car, but the number of kilometers traveled and the guarantee factor of the car should be very different. The waterproofing, deformation resistance, and processing technology of outdoor screens are the same as those of key accessories. A slight deviation can make a huge difference.
In addition to considering the quality of major components such as LEDs and ICs, prior communication with the seller is also very important. It not only directly affects the quality, success or failure of the entire project, but also often allows users to allocate invested resources more rationally, avoid unnecessary waste, losses and hidden dangers, and even increase considerable profits.
Manufacturers should also take the initiative to provide users with simulation solutions or better suggestions based on actual needs and operability, and help customers make reasonable analysis and planning, and make the most cost-effective solution, in order to become users’ trustworthy partners. Communication matters generally include the following points:
1. Be clear about your needs, investment budget and expected best results;
2. Describe the needs for the project and future development plans in detail, and require the seller to provide the best implementation plan, even the project’s expandable functions and expansion budget and plan, to avoid unnecessary inconveniences caused by the project not being suitable for future development needs. Waste of resources;
3. Provide or require manufacturers to analyze data on the project installation and application environment, predict possible events and propose preventive and solution measures, and then make a comprehensive assessment of the entire project plan;
4. Different LED production processes, screen assembly processes, and installation technical experience will directly affect the construction period, cost, safety performance, display effect and quality, service life, and maintenance costs of the entire project. Therefore, it is necessary to understand in advance from the manufacturer or multiple aspects. Compare the performance characteristics of various aspects of products and projects and choose the solution that best suits your needs;
5. Understand the strength, integrity, service content and quality of the manufacturer. These are the foundation and guarantee for good and long-term cooperation in the project.
