[Full-color LED display] Is the dead lamp of full-color LED display not good for the tube core?
Visit：2839 Date：2019-04-16
Full-color LED displays are among the popular electronics and are currently used in many areas. The use of LED products will also appear dead lights. Regarding the maintenance of full-color LED display screens, we will analyze the problem of full-color LED display dead lights caused by the die process. Is the full-color LED display dead light a bad die?
We often encounter LEDs that are not bright. It is impossible to block the enterprises, use the enterprises, and the units and individuals that are used. 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 is too large to form a PN junction failure, so that the LED light is not bright, and that kind of situation generally does not affect the work of other LED lights; Second, the internal connection leads of the LED lamp are disconnected, forming a full-color LED display without a current to generate a dead light, and that kind of situation will affect the general work of other LED lamps, the reason is that the LED lamp work has a low voltage ( Red yellow orange LED work voltage 1.8V-2.2V, blue green white LED work voltage 2.8-3.2V), generally have to use string, parallel to connect, to work with different work voltage, series full color LED display The more influence the screen light has, the less the internal wiring of the LED light is open, and the zero-string LED light that forms the series circuit is not bright. It can be seen that the situation is more severe than the first type. LED dead lights are the key to affecting the quantity and reliability of production. How to reduce and eliminate dead lights and increase the quantity and reliability of production is a key issue that needs to be dealt with by enterprises.
1. Static electricity damages the LED chip, causing the PN junction of the LED chip to fail, and the leakage current is reduced to become a resistor.
Static electricity is a kind of destructive devil. The world's electronic components damaged by static electricity are countless, resulting in tens of millions of dollars in economic loss. Therefore, it is a major task in the electronics industry to prevent static electricity from damaging electronic components. Enterprises that use LEDs to seal and use should not be taken lightly. Any problem in one of the links will cause damage to the LED, causing the LED performance to deteriorate and fail. We know that the human body (ESD) static electricity can reach three thousand volts left and right, the foot can break down the LED chip, and the LED sealing and dismantling production line, the grounding resistance of various equipment can meet the requirements, it is also very important, generally requires grounding The resistance is 4 ohms, and the grounding resistance of the case where there is no high requirement is such that it is ≤ 2 ohms.
The damage of the human body static electricity to the full-color LED display is also very large. When wearing the anti-static clothing, it is equipped with an electrostatic ring. When the electrostatic ring is grounded, there is no antistatic effect of the static ring that does not need to be grounded. It is not good. It is recommended not to use this type of product. If the worker violates the operating procedures, he or she will receive a considerable warning education and also use it to inform others. The amount of static electricity in the human body is related to the different fabrics worn by people and the volume of each person. When we undress in autumn and winter, it is very difficult to see the discharge phenomenon between clothes. The voltage of electrostatic discharge is no more than three thousand. Volt. The ESD value of the silicon carbide substrate chip is only 1100 volts, and the ESD value of the sapphire substrate chip is lower, as long as 500-600 volts. A good chip or LED, if we take it by hand (the body does not do any protective measures), the result can be imagined, the chip or LED will be damaged to varying degrees, a good device from time to time through us The hand is inexplicably broken, and that is the fault caused by static electricity.
If the company is not strictly in accordance with the grounding rules, it will be the company itself, which will reduce the qualified rate of products and reduce the economic efficiency of the enterprise. The same use of full-color LED display enterprises will also form LEDs if the equipment and personnel are poorly grounded. Damage, rework is inevitable. According to the requirements of the LED standard manual, the lead wire of the LED is not less than 3-5 mm, and is bent or soldered, but most of the enterprises have not done that, but only the thickness of a PCB board ( ≤ 2 mm) is indirectly welded, it will also damage or damage the LED. Because the excessive soldering temperature will affect the chip, the chip characteristics will be deteriorated, and the luminous efficiency will be reduced, resulting in damage to the LED. This kind of phenomenon is not uncommon. .
The maintenance of full-color LED display is relatively simple, which is one of the reasons why the full-color LED display is popular in the outdoor large screen. Many full-color LED display manufacturers have corresponding after-sales technicians to solve the full-color The LED display is in an unexpected situation during use, so the analysis of the structure and performance of the entire full-color LED display is still important.
