Ultra-low temperature outdoor led display solution
Everyone knows that some countries or regions have a temperature below 0 °C for most of the year and even below -30 °C at night. The LED display in this area will cause the power on the display to be unsuccessful when the ambient temperature is too low.
For the LED display installed outdoors, the winter is a long and rigorous test, because the temperature of the lower than 20 degrees of temperature, the composition of the LED display materials due to its thermal expansion and contraction coefficient is different, its physical size changes Inconsistent, prone to large gaps or extrusion bumps or even bursts between modules, resulting in LED display waterproof and dustproof failure and obvious mosaic phenomenon.
In addition, in the case of extremely low temperatures, some electronic components are not working properly, so that the entire screen cannot operate normally.
Through the complete limit temperature simulation environment test, our outdoor LED display has passed the test of -35 ° C ~ 85 ° C simulation temperature and humidity test room before leaving the factory, we fully consider the harsh environment that the display may bear in the future. Well, the corresponding corresponding measures, whether from the iron box, lamp, electronic components, or the bottom cover of the display screen, have been carefully considered and carefully selected. For ultra-low temperature LED display design, we have formed a unique solution.
1. Using ultra-low temperature power supply
Japan TDK ultra-low power supply, Taiwan Ming Wei ultra-low temperature power supply, Changzhou Chuanglian ultra-low temperature power supply, Shenzhen Xinxing ultra-low temperature power supply, etc. can achieve -40 ° C; -25 ° C environment to start. Among them, when the low temperature environment is close to the power supply temperature limit (such as ultra-low temperature at -35 °C), the power load power will be derated, and the derating range is close to 50%.
2. Install a hot air curtain inside the LED display
A closed channel is formed inside the large screen, and a hot air axial flow is added at the rear, and the working state of the hot air axial flow is realized by the temperature control system. When the temperature is lower than the set minimum ambient temperature, the hot air fan is heated, the temperature of the screen body rises, and then the screen body is opened. When the temperature reaches the set temperature, the temperature control system cuts off the alternating current power supplied to the hot air blower.
3. Power supply, PCB circuit board "three defense" processing
The outdoor LED electronic display is in the open air environment for a long time, so it is required to resist high and low temperature, waterproof fog and anti-corrosion performance of PCB circuit board, power supply and solder joints. Our company comprehensively carries out “three-proof” treatment on PCB circuit boards, components and solder joints in outdoor electronic display system. Circuit board three-proof paint is a special formula coating for protecting circuit boards and related equipment. Corroded by the environment, thereby increasing and extending their service life, ensuring the safety and reliability of use.
The three anti-paint is applied to the exterior of the circuit board to form a film that is both light and flexible and only 25-50 microns thick. It protects the circuit from damage, such as with chemicals (eg fuel, coolant, etc.), vibration, moisture, salt spray, moisture and high temperatures, and low temperatures. Under these conditions, the board may be corroded, mold growth, and short circuit, etc., resulting in failure of the circuit using the three anti-paint.
Our company believes that for the display system, which has a long service life, poor use environment and a large number of components, in order to ensure the reliability of the display, it is necessary to strictly control the three defenses of the display. Invasion prevention process. In addition, the use of current-carrying welding technology, objectively eliminate the damage of the rosin left in the manual solder to the three defenses, to achieve a true full "three defense" process.
4. Using low temperature sheet metal box
The northern part of the snowy mountains is a place that many people yearn for, but it is a long test for LED displays, because the temperature here often reaches minus 30 degrees or even lower. At this temperature, the display The box shrinks due to the principle of thermal expansion and contraction, which causes the gap between the box and the box to become larger - and even the same row of tubes is not on the same line, which makes the whole screen form a block. Big mosaic phenomenon.
After research and development experience, it is made of high-quality steel plate, and the whole body is treated by hot-dip galvanizing process. During the processing of the box, the metal surface is cleaned and blasted to remove rust; oxidized galvanizing on the metal surface Treatment to prevent surface oxidation and corrosion; surface baking or acid-proof spray treatment to effectively prevent acid rain and fog.
5. Targeted materials for ultra-low temperature environments
The prerequisite for the quality of LED display is the quality of the original device. There is no high-quality raw material. No equipment or process can produce advanced high-quality products. Therefore, the key materials of this project are high-quality devices, especially electronic devices. Such as PCB, led lamp beads, drive IC, capacitor resistance, three anti-paint.
6. Using antifreeze epoxy resin
Compared with glycidyl ester epoxy resin, glycidyl ester epoxy resin and diphenol propane epoxidized resin, it has low viscosity, good processability, high reactivity, and higher adhesion than general epoxy resin. The cured product has good mechanical properties; good electrical insulation; good weather resistance, and good resistance to ultra-low temperature. Under ultra-low temperature conditions, it still has higher bonding strength than other types of epoxy resin. It has good surface gloss, good light transmission and weather resistance.