Outdoor LED display of the pros and cons to judge
Today's society, the rapid development of the case, outdoor led large screen applications will be more and more widely, but the quality of uneven, leading to frequent accidents, then how do we judge the outdoor LED is good or bad?
In the led display, the most important thing is the LED lamp beads, and the lamp is good or bad impact led display quality. LED lamp beads is the most used in the full color screen machine the most important components, each square meter will use thousands to tens of thousands of lamp beads, lamp beads is also the decision of the whole screen optical display performance of the main, directly affect the audience evaluation of the display , Lamp beads in the overall cost of the display is also the largest proportion, ranging from 30% to 70%. The importance is immediately highlighted.
In the field of LED display, the most important one is the brightness of the index, the brightness of the high demand, the heat will become a big problem, the heat is the LED field whether it is lighting or display is a relatively long problem. The major manufacturers have launched their own thermal solutions, the declaration of their own product cooling effect has become a hard target. Another reason is that with the small pitch LED research and development, junction temperature problem has always been difficult to solve.
So how to identify the advantages and disadvantages of led lamp beads?
First: see the brightness, that is, we usually say how much you can achieve the lamp beads LM (lumens), LM (lumens) is a measure of the brightness of the lamp unit
Second: to see whether the uniform color is uniform, the quality of the light beads are very uniform light, consistent color. Poor quality of the lamp beads will appear a lamp beads bright, a lamp beads dark phenomenon, luminous color mess is not uniform, there will be a clear dark area.
Third: look at the chip and chip size, the chip is the decisive factor in the quality of the lamp beads, under normal circumstances the greater the stability of the chip, the higher the brightness, the better the heat.
Fourth: look at the glue and phosphor, the general good products will use imported glue, the package is good light beads by hand without deformation, low quality glue will be a deformation or even cracking and so on.
Fifth: to see the bracket, the general situation for the silver-plated copper bracket bracket, silver plated copper bracket is the advantage of fast heat, you can better to the lamp beads heat, small resistance. Some businesses on the market will use ceramic stents instead of silver-plated copper brackets, ceramic stent thermal conductivity is excellent
Sixth: see the packaging process, good quality LED lamp beads uniform color, colloidal consistency is good. This is inseparable from the good machinery and equipment, production machinery and equipment is a key factor, good equipment can ensure that the product in the various procedures on the stability and consistency, to protect the product yield.
In fact, the most important, or look at the lamp beads of the chip, the chip directly determines the color rendering index, brightness, anti-attenuation level.
Chip in the case of high junction temperature, the light will be very serious decline, the first thermal contact body is the substrate, the substrate will directly determine the heat conduction temperature situation, the current well-known manufacturers, some have begun to use the new ceramic as Substrate material.
Ceramic substrate as the current market, the best heat dissipation of the substrate, than the aluminum plate, silicon substrate, sapphire substrate thermal conductivity, stability should be good. Ceramic substrate is mainly aluminum nitride, alumina two, of which the thermal conductivity of aluminum nitride can reach 170 (W / (m · K) ~ 230 (W / (m · K). Is twice the alumina substrate Above. This thermal efficiency, LED lamp beads will not have a junction temperature, there is no heat problem.