Publisher: Supplier of LED Display Time: 2022-02-22 14:08 Views: 1183
Everyone knows that in some countries or regions, most of the year-round temperatures are below 0°C, and even below -30°C at night. When the ambient temperature of the LED display in this area is too low, the power on the display will fail to turn on.
For the LED display installed outdoors, the cold winter is a long and severe test, because under the temperature of minus 20 degrees, the various materials that make up the LED display have different coefficients of thermal expansion and contraction, and their physical dimensions change. Inconsistency, it is prone to large gaps or extrusion bulges or even bursts between modules, resulting in waterproof and dustproof failure of the LED display and obvious mosaic phenomenon. In addition, in the case of extremely low temperature, some electronic components can not work normally, making the whole screen unable to work normally.
Through the complete extreme temperature simulation environment test, the outdoor LED display of LCF Group has passed the test of -35℃～85℃ simulated temperature and humidity laboratory before leaving the factory. We have fully considered the harsh environment that the display may have to withstand in the future. Corresponding measures have been taken, no matter from the iron box of the display screen, the lamp tube, the electronic components, or the bottom shell mask, etc., have been carefully considered and selected.
For the design of ultra-low temperature LED display, LCF has formed a set of unique solutions:
1. Using ultra-low temperature power supply: Japan's TDK ultra-low power supply, Taiwan Mingwei ultra-low temperature power supply, Changzhou Chuanglian ultra-low temperature power supply, Shenzhen Nova ultra-low temperature power supply, etc. can be started in the environment of -40°C; -25°C.
Among them, when the low temperature environment is close to the temperature limit of the power supply (for example, ultra-low temperature is used at -35°C), the load power of the power supply will be derated, and the derating range will be close to 50%.
2. Install a hot air curtain inside the LED display screen: make a closed channel inside the large screen, and install a hot air axial flow at the rear. 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 blower is heated, the temperature of the screen body rises, and then the screen body is turned on. When the temperature reaches the set temperature, the temperature control system cuts off the AC power supplying the hot air blower.
3. "Three-proof" treatment of power supply and PCB circuit boards: Outdoor LED electronic display screens have been in the open air for a long time, so PCB circuit boards, power supplies, solder joints, etc. are required to be resistant to high and low temperature, waterproof fog, and corrosion resistance. Our company conducts "three-proof" treatment on PCB circuit boards, components, solder joints, etc. in the outdoor electronic display system. Corrosion by the environment, thereby improving and prolonging their service life, ensuring the safety and reliability of use. The conformal paint is applied to the surface of the circuit board to form a light and flexible film with a thickness of only 25-50 microns. It protects circuits from damage under conditions such as chemicals (eg fuel, coolant, etc.), vibration, moisture, salt spray, humidity and high and low temperatures. Under these conditions, the circuit board may be corroded, mold growth, and short-circuiting, etc., resulting in failure of circuits without conformal paint. Our company believes that for the display screen, which has a long service life, poor use environment and a large number of components, in order to ensure the reliability of the display screen, it is necessary to carry out strict process control on the three defenses of the display screen. Intrusion Prevention" process. In addition, the use of current-carrying welding technology objectively eliminates the damage to the three defenses caused by the rosin left in the manual soldering, and achieves a real "three defenses" process.
4. Using anti-low temperature sheet metal box: the snow-capped north is a place that many people yearn for, but it is a long test for the LED display, because the temperature here often reaches minus 30 degrees or even Lower, at this temperature, the box of the display screen shrinks due to the principle of thermal expansion and cold contraction, which will cause the gap between the box and the box to become larger-, and even cause the same row of lamps not to be in the same straight line , which makes the whole screen form a large mosaic phenomenon.
After years of research and development experience, it is made of high-quality steel plates. The whole box is treated by hot-dip galvanizing. During the processing of the box, the metal surface is cleaned and sandblasted to remove rust; the metal surface is oxidized. Galvanized treatment can prevent surface oxidation and corrosion; surface paint or anti-acid spray treatment can effectively prevent the erosion of acid rain fog.
5. Use targeted materials for the ultra-low temperature environment: The prerequisite for the quality of the LED display is the quality of the original components. Without high-quality raw materials, advanced and high-quality products cannot be produced with any equipment and process. Therefore, the key to this project is The materials are made of high-quality devices, especially electronic devices, such as PCB, led lamp beads, driver IC, capacitors and resistors, three-proof paint, etc.
6. The use of antifreeze epoxy resin: using glycidyl ester epoxy resin, glycidyl ester epoxy resin and diphenol-based propane epoxidized resin, it has low viscosity, good workability and high reactivity; The adhesive force is higher than that of general-purpose epoxy resins, and the cured material has good mechanical properties; good electrical insulation; good weather resistance, and has good ultra-low temperature resistance. knot strength. It has good surface gloss, good light transmittance and weather resistance.