LED display pixels out of control elements of the primary reason is the failure of LED, and LED failure can be divided into two main reasons: 1.LED itself is not good quality; 2.
Many LED failures are usually not found in the LED routine test. In addition to being subjected to electrostatic discharge, high current (forming junction temperature too high), external strength and other improper use, many LED failure is in the high temperature, low temperature, temperature change or other harsh conditions, because the LED chip, epoxy Resin, stent, inner lead, solid crystal, PPA cup and other information, the difference between the thermal expansion coefficient, triggering its internal stress is not the same as the occurrence.
LED quality inspection is a very complex operation. Furthermore, for GaN-based LEDs, electrostatic discharge is the biggest incentive for its failure. Electrostatic discharge caused by the mechanism of LED failure is very complex, equipment, things, utensils and the human body are able to have static electricity and its discharge, this static as little as a few hundred volts, high tens of thousands of volts, discharge time in nanosecond level The We in the display production, installation, the use of the process of the blue-green tube failure, often LED-PN junction is electrostatic discharge breakdown. The World Association of Electrostatics is strictly regulated in the form of electrostatic discharge, mainly in the form of human body discharge (HBM) and machine discharge (MM). China's electrostatic discharge sensitivity of the equipment (ESDS) is divided into three grades (human form): 1 for 0 ~ 1999V; 2 for 2000 ~ 3999V; 3 for more than 4000V.
Often the LED electrostatic discharge sensitivity in the human body in the form of hundreds of volts to tens of thousands of volts, and in the form of the machine as long as tens of volts to five hundred volts or so. LED display because of the production process is complicated, electrostatic discharge is hard to detect, therefore, LED electrostatic discharge sensitivity should be selected 2 or more for the (human form), and electrostatic protection is necessary throughout the production process.