The service life of the main materials of led full-color large screen (a kind of LED display screen, also called LED large screen, etc.). ) is 654.38+ 10,000 hours, running at 365 days/year and 24 hours/day, and its service life exceeds 654.38+065.438+0 years, so most customers only care about using well-known led and IC. In fact, these two are only necessary conditions, not sufficient conditions, because the reasonable use of red, green and blue lights is more important to the display screen, and a good display screen is more important to make the lights of different colors work in the best condition. Reasonable adjustment of IC is also helpful to overcome the problem of unreasonable PCB wiring. Just like a car, if the engine is good and the circuit is well controlled, it does not necessarily become a good car. The key factor is this: As both LED and IC are semiconductor devices, they have strict requirements on environmental conditions. The room temperature is preferably around 25℃, and their working mechanism is the best. But in fact, outdoor large screens will be used in different temperature environments, which may be above 60℃ in summer and below -20℃ in winter. When manufacturers produce products, different products are classified into different grades with 25℃ as the test condition, but the actual operating conditions are 60℃ or -20℃. At this time, the working efficiency and performance of LED and IC are inconsistent, and the original ones will become multi-grade and the brightness will be inconsistent, and the screen body will naturally become colorful. This is because the brightness attenuation and decline of red, green and blue lamps are different under different temperature conditions. At 25℃, the white balance is normal, but at 60℃, the brightness of the three colors of LED decreases, and their attenuation values are inconsistent, so the brightness of the whole screen decreases and color cast occurs, and the quality of the whole screen decreases. And IC? The operating temperature range of integrated circuits is -40℃-85℃. The outside temperature is too high, which leads to the temperature rise in the box. If the temperature in the box exceeds 85℃, the IC will be unstable because of the high temperature, or the current between channels or the difference between chips will be too large, resulting in the screen.
At the same time, power supply is also very important. Because of the different working stability, output voltage value and load capacity of the power supply at different temperatures, its supporting capacity directly affects the quality of the screen, because it plays the role of logistics support.
The box design is also very important for LED 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 is dustproof and waterproof. But more importantly, the thermal circulation system of ventilation and heat dissipation is well designed. With the extension of start-up time and the increase of external temperature, the thermal drift of components will also increase, resulting in poor image quality.
These factors are interrelated and will affect the quality and life of the display screen. Therefore, when customers choose the screen, they should also make a comprehensive observation and analysis and make a correct judgment. The influence of temperature on the big screen is not limited to this. Suppose a customer buys a large screen, with a width of 10 meter and a height of 6 meters (60 square meters). Although the total area is small, the internal components are all kinds of unit boxes, and the temperature between the unit boxes is not necessarily balanced. The temperature inside the box will also be affected by air convection, resulting in different temperatures between the unit boxes or inside the unit boxes, resulting in inconsistent working efficiency of semiconductor devices, thus showing the luminous brightness of LED lamps.
Don't underestimate the outdoor temperature, just think about the example of boiling eggs in the car in summer. What's more, the LED display is still bright in the case of summer exposure. (the light emitted is more effective than the intensity of the sun), and its luminescence will definitely heat up. These are all influencing factors.
Not only fragile and delicate semiconductor devices such as LED and IC, but also solid ABS, masks, iron boxes, connectors and various solder joints are struggling in hot and cold temperatures. Under the multiple attacks of sunlight exposure and moisture after freezing rain at low temperature, the mask is deformed and warped locally by 2-3mm, and ultraviolet radiation also changes the color of the mask board, so that the mask board seen by the audience will change color and appear spots under various climate changes in a year. Deformation will also affect the bending of PCB, resulting in unreliable solder joints, resulting in virtual soldering and LED switching. Moreover, due to the humidity and oxidation of the air, the oxidation contact surface of the connector is reduced, and the micro-scale coating of the connector does not form close contact, which leads to the interruption of signal or power supply and the failure of the large screen.
Deformation and mechanical fatigue will also affect the iron box and the outer frame, resulting in uneven screen body, the module and the iron box can not cooperate closely, and some of them leak water and other consequences.
Therefore, to choose a good LED display screen, we must choose a good lamp tube for the first line, which is durable and adaptable, and other materials and processes should not be underestimated. Just like a car, several people's repair shops can piece together a car, and tens of thousands of people's factories are also assembling a car, but the mileage and guarantee coefficient of the car should be far from each other. The waterproof, anti-deformation, processing technology and key accessories of outdoor screens are the same, but the difference is only a fraction.