Full-color LED displays belong to the category of popular electronic products and are currently used in many fields. The use of LED products will also cause dead lights. Regarding the maintenance of full-color LED displays, let's analyze the dead lights of full-color LED displays caused by the die process. Is the dead light of the full-color LED display a bad die?

  We often encounter the situation that the LED does not light up. It is impossible for the packaging and dismantling enterprises, using enterprises, and using units and individuals to encounter them. That is the phenomenon of dead lights that people in the industry say. The reason is nothing more than two kinds of situations: First, the leakage current of the full-color LED display screen is too large to cause the PN junction to fail, so that the LED light does not light up, and that kind of situation generally does not affect the work of other LED lights; Second, the internal connection lead of the LED light is disconnected, resulting in a dead light without current passing through the full-color LED display. This kind of situation will affect the general operation of other LED lights. The reason is that the operating voltage of the LED light is low ( The working voltage of red, yellow and orange LEDs is 1.8V-2.2V, and the working voltage of blue, green and white LEDs is 2.8-3.2V). Generally, series and parallel connections are used to facilitate different working voltages. The series-connected full-color LED displays The more screen lights, the greater the impact. As long as there is no open circuit inside the LED lights, the zero string LED lights forming the series circuit will not light up. It can be seen that this type of situation is much more severe than the first type of situation. LED dead lights are the key to affecting the production volume and reliability. How to reduce and eliminate dead lights and improve the production volume and reliability are the key issues that need to be dealt with by the packaging, demolition and use enterprises.

   1. Static electricity damages the LED chip, causing the PN junction of the LED chip to fail, increasing the leakage current and turning it into a resistor.

   Static electricity is a kind of devil that is extremely harmful. There are countless electronic components damaged by static electricity in the world, resulting in economic losses of tens of millions of dollars. Therefore, preventing static electricity from damaging electronic components is a very important task in the electronics industry. Enterprises that package and use LEDs must not take it lightly. Any problem in any link will cause damage to the LED, making the performance of the LED worse and failure. We know that the static electricity of the human body (ESD) can reach about 3,000 volts, and the feet can break down and damage the LED chip. In the LED packaging and disassembly production line, whether the grounding resistance of various equipment can meet the requirements is also very important. Generally, grounding is required. The resistance is 4 ohms, and the grounding resistance should reach ≤ 2 ohms in some high-demanding occasions.

   The damage of human body static electricity to the full-color LED display is also very great. When working, wear anti-static clothing and remove it, with an electrostatic ring. No, it is recommended not to use this type of product. If the staff violates the operating procedures, they should receive a considerable warning and education, and also serve as a notice to others. The amount of static electricity in the human body depends on the different fabrics and clothes people wear and their body weight. It is difficult to see the discharge phenomenon between clothes when we take off our clothes in autumn and winter. Volt. The ESD value of silicon carbide substrate chips is only 1100 volts, and the ESD value of sapphire substrate chips is even lower, only 500-600 volts. A good chip or LED, if we take it with our hands (the body does not take any protective measures), the result can be imagined, the chip or LED will be damaged to varying degrees, and a good device will pass through us from time to time. The hand is inexplicably broken, and that is the fault of static electricity.

   If the packaging and demolition enterprises do not strictly follow the grounding regulations, the enterprise itself will suffer, which will result in a decline in the product qualification rate and reduce the economic efficiency of the enterprise. Similarly, if the equipment and personnel are poorly grounded, LEDs will also be formed in enterprises using full-color LED displays. Damage, rework is inevitable. According to the requirements of the LED standard manual, the lead of the LED should be no less than 3-5 mm away from the colloid, and the legs should be bent or welded, but most users do not do that, but only the thickness of a PCB board ( ≤2mm), it will be indirectly welded, which will also cause damage or damage to the LED. Because the excessive welding temperature will affect the chip, the chip characteristics will be deteriorated, the luminous efficiency will be reduced, and the LED will be damaged. Such phenomena are not uncommon. .