2016-07-28
1. Viewing angle
The viewing angle of display depends on that of lamp. Nowadays, outdoor displays usually take lamp with viewing angle of horizontal 100 and vertical 50; while indoor ones take SMD with horizontal 120 and vertical 120. Round LED with viewing angle of 30 is enough for those displays used in highway due to its specialty. Besides, some displays used in high buildings needs high vertical viewing angle. Viewing angle is incompatible with brightness, thus a higher viewing angle is sure to be with a lower brightness. How to choose viewing angle depends on the function of the display.
2. Brightness
The brightness of LED is a key point of the display. The higher the brightness is, the higher the allowance of electricity is, which is helpful to save energy and keep the stability of LED. There are different viewing angle of LED. In the case of a certain brightness of Chip, the brightness of LED is inversely proportional to the viewing angle. Normally, we choose LED with brightness of 100 to maintain a good viewing angle.
3. Failure rate
Since the full-color display is composed of ten or even hundred thousands of red, green, and blue LED pixels dots, the failure of any LED of any color will affect the overall visual effect. In general, the failure rate of the LED screen which caused by the beads themselves should be no higher than three in ten thousand between the time of assembly and aging for 72 hours before shipment according to industrial experience.
4. Anti-static capability
LED is a semiconductor device, sensitive to static electricity which can easily cause failure, so the antistatic ability is critical to the display lifespan. Generally speaking, the test failure voltage of LED under static mode should be no less than 2000V.
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