How to buy a good LED display?

After several years of development, LED full-color large screens seem to be a mature industry at first glance. In fact, whether it is domestic or foreign manufacturers, there is still a long way to go, especially for outdoor large screens. After two years of operation, most of the products , it is difficult to maintain within the user’s expectations.

Why is this so?

First of all, there is a big misunderstanding here. Most people think that the main materials of the screen, LED and IC, have a lifespan of 100,000 hours. According to 365 days/year, 24 hours/day operation, the service life is more than 11 years, so most customers only care about it. Use 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 to the display screen. For lamps of different colors, it is necessary to make them work in the best state. A good display will be even more important. Reasonable adjustment of IC also helps to overcome the unreasonable wiring problem of PCB. Just as if a car has a good engine and circuit control, it does not necessarily make it a good car. The key factors here are:

Since LEDs and ICs are semiconductor devices, they are picky about the conditions of use in the environment, preferably at a room temperature of about 25°C, and their working mechanism is the best. 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 the manufacturer produces products, they use 25°C as the test condition to classify different products into categories. However, the operating conditions are actually 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 same level. It will become multi-level, the brightness will be inconsistent, and the screen will naturally become blurred. This is because under different temperature conditions, the brightness attenuation and drop of the red, green, and blue lights are different. At 25°C, the white balance is normal, but at 60°C, the three colors of LED The brightness of the screen has decreased, and its attenuation value is inconsistent, so the phenomenon of decreased brightness and color cast of the entire screen will occur, and the quality of the entire screen will decrease. And what about ICs? The operating temperature range of the IC is -40°C to 85°C. Due to the high external temperature, the temperature in the box rises. If the temperature in the box exceeds 85°C, the IC will work unstable due to the high temperature, or the current between channels or the difference between chips will be too large due to different temperature drifts. Cause Huaping.

At the same time, the power supply is also very important. Because the power supply is under different temperature conditions, its working stability, output voltage value and load capacity will also be different. Because it is responsible for logistics support, its support ability directly affects screen quality.The cabinet design is also very important for the display screen. On the one hand, it has the function of circuit protection, on the other hand, it has the function of safety, and it also has the functions of dustproof and waterproof. But what is more important is whether the design of the thermal loop system for ventilation and heat dissipation is good. With the extension of the startup time and the increase of the external temperature, the thermal drift of the components will also increase, resulting in the deterioration of the image quality.

These factors are interrelated and will affect the quality and life of the display. Therefore, when customers choose screens, they must also conduct comprehensive observation and analysis to make correct judgments.

The impact of temperature on the large screen is not only that, assuming that the customer buys a large screen with a width of 10 meters and a height of 6 meters (60 square meters). Although the total area is not large, the internal composition is each unit box. The temperature is not necessarily balanced, and the temperature in the box will also be affected by air convection and the temperature will be inconsistent, resulting in differences in the temperature between the unit boxes or inside the unit box, resulting in inconsistent working efficiency of semiconductor devices, which is manifested as LED lights. The brightness is inconsistent, and the screen looks “flowery”. Don’t underestimate the outdoor temperature. You only need to think about the example of boiled eggs in a car in summer. What’s more, the LED display still needs to emit light under the summer sun. (The emitted light must be stronger than sunlight to be effective), and its luminescence will definitely generate heat, these are all influencing factors.

It is not only fragile and delicate semiconductor devices such as LEDs and ICs that struggle against hot and cold temperatures, but also sturdy ABS, masks, iron boxes, connectors, and various soldering points. Under the multiple impacts of air, partial deformation and warping angles can reach up to 2-3mm. In addition, ultraviolet radiation can also change the color of the mask board. In this way, under a variety of climate changes throughout the year, the mask board itself seen by the audience will change color. Spot plate, deformation will block the light-emitting angle of the luminous tube to produce dark areas of light; deformation will also affect the curvature of the PCB board, resulting in unreliable solder joints, resulting in virtual soldering that makes the LED turn on and off. Moreover, due to the moisture and oxidation of the air, the oxidized contact surface of the connector is reduced, coupled with the subtle influence of vibration and deformation, the micron-level plating of the connector does not form a tight contact, resulting in signal or power interruption, and the large screen fails.

Deformation and mechanical fatigue will also affect the iron box and the outer frame, resulting in uneven screen body, inability to tightly fit the module and the iron box, partial water leakage and other consequences.Therefore, to choose a good large screen, the first line must be to choose a good lamp tube, 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 be pieced together. For a car, a factory with tens of thousands of people is also assembling a car, but the number of kilometers traveled by the car and the guarantee factor should be far apart. The waterproof and anti-deformation of the outdoor screen, the processing technology is the same as the key accessories, and the difference is a thousand miles.In addition to considering the quality of main components such as LEDs and ICs, prior communication with the seller is also very important. It not only directly affects the quality and success of the entire project, but also often allows users to allocate resources more reasonably, avoid unnecessary waste, loss and hidden dangers, and even increase considerable profits.

Manufacturers should also take the initiative to provide users with simulation solutions or better suggestions on actual needs and operability, and help customers analyze and plan reasonably, and make the most cost-effective solutions, in order to become users’ reliable partners. Communication items generally include the following points:

1. Be clear about your needs, investment budget and expected best results;

2. Indicate in detail the demand for the project and the future development plan, and require the seller to provide the best implementation plan, and even the expandable function of the project and the expansion budget and plan, so as to avoid unnecessary trouble caused by the project not being suitable for future development needs. waste of resources;

3. Provide or require manufacturers to analyze data on project installation and application environment, predict possible incidents and propose preventive and solution measures, and then make a comprehensive evaluation of the entire project plan;

4. Different LED production process, screen assembly process and installation technology experience will directly affect the construction period, cost, safety performance, display effect and quality, service life and maintenance cost of the entire project. Therefore, it is necessary to understand from the manufacturer or various aspects in advance Compare the performance characteristics of all 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 basis and guarantee for a good and long-term cooperation in the project.

Consume clearly and use it easily. I wish every customer who needs to use a large screen can buy a product that he is satisfied with. I also wish that the large-screen display industry will eliminate the inferior and save the superior under the constant requirements of users, and achieve A higher level of quality.