Outdoor LCD signs focus on heat dissipation and dust protection. Dust protection is not only a thermal design but also a structural design. By the diameter and quantity of outdoor dust particles checked in data, it can be determined that the outdoor dust prevention requirements are ≤1μm, which means the filter efficiency F7 or above.
Some users may ask: How long does it take to clean or replace the filter for outdoor signage with F7 or other grades of filter? At present, a few outdoor signage manufacturers keep budgets low due to competition, making the filter itself low as well in efficiency, such as G4 grade or even lower, as a result, a lot of large particles of dust can pass. However, the life of the filter could be longer, because the dust with diameter of ≤ 5 μm are allowed into the chassis. As long as the outdoor LCD sign continues to work for more than a month, there would be a lot of dust between air duct OC and tempered glass in front of the screen. Once the display screen is turned off, the dust inside the glass will be more obvious, and there will be a lot of dust on the back of the screen. The PCB board will also accumulate with dust, and the display effect becomes poor, and the failure rate becomes high. Thus, with an effective dust-proof filter, the cost is high (under the same size, F7 is expected to be 4~5 times more than the price of G4), the dustproof is good, however. Only then is it meaningful to consider the period for filter replacement.
As a developer, Suntune’s design concept is that the size of the filter achieves maximum according to the internal space of the whole outdoor signage, so it can meet the replacement once in 2-3 years, or at least 1 year if the equipment is individually thin while the interior space limited. The main reason is that the cost is too high for outdoor maintenance. Filter replacement period is a consideration for thermal design. When the temperature between the internal and the external exceeds the critical point of the thermal design, and the air in the chassis is kept at a high temperature ( 60 °C or above), it’s time to consider changing the filters.
Some users may think that the high-brightness LCM with wide temperature OC will not get black screen. As mentioned earlier, the wide temperature OC can withstand temperature more than 100 °C before going to blacken, but the state of high brightness LCM has a limited temperature, over which it will inevitably cause the backlight decay fast, the OC yellowing, the lines, the optical diaphragm wrinkles, the electronic component life shortening and other problems. Therefore, the calculation of air volume, impedance and fans selection is directly related to the size, impedance and life of the filter.
In general, the larger the filter size, the better; the larger the dust capacity, the longer the life. However, at present, outdoor signage pursues light and beautiful appearance, which makes there not much space to place the filters, so the design should reasonably calculate the air volume, wind speed, fan P-Q curve in order to determine the filter size.
AT THE END OF THIS ARTICLE, SUNTUNE CALLS ON INDUSTRY MANUFACTURERS TO PAY ATTENTION TO TECHNOLOGY RESEARCH AND DEVELOPMENT, IMPROVE THE QUALITY, AND CREATE A THRIVING DEVELOPMENT OF OUTDOOR LCD SIGNAGE.