Many customers will find dead lights when using LED SMD lamp beads. Very often, the project has been looking for a long time and can't find out what the problem is. Expanding the optoelectronic project provides you with the following points. If you encounter the following situations, You can refer to:
1. Static electricity damages the LED chip, causing the PN junction of the LED chip to fail, increasing the leakage current, and turning into a resistance. Static electricity is a very harmful devil. There are countless electronic components damaged by static electricity all over the world. 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, and LED packaging and application companies must not take it lightly. Any problem in any link will cause damage to the LED, and cause the performance of the LED to deteriorate or even become invalid. A good chip or LED, if we take it by hand (without any protective measures on the body), the result can be imagined. The chip or LED will be damaged to varying degrees. Sometimes a good device passes through our hands. It is inexplicably broken, this is the fault of static electricity.
2. Some small companies use manual soldering and use a 40-watt ordinary soldering iron. The soldering temperature cannot be controlled. The soldering iron temperature is above 300-400℃. Excessive soldering temperature can also cause dead lights. The expansion coefficient of LED leads is 150 at high temperatures. The coefficient of expansion at about ℃ is several times higher, and the internal gold wire solder joints will be pulled apart due to excessive thermal expansion and contraction, resulting in dead lights.
3. Analysis of the causes of the dead light phenomenon caused by the open circuit of the solder joints in the LED light
4. The incomplete production process of packaging enterprises and the backward inspection methods of incoming materials are the direct causes of LED dead lights
5. Generally, LEDs are packaged in bracket rows. The bracket rows are made of copper or iron metal materials by precision die stamping. Because copper is more expensive, the cost is naturally high. Affected by the fierce competition in the market, in order to reduce manufacturing costs, Most of the market uses cold-rolled low-carbon steel to stamp LED stents. The iron stents must be silver-plated. Silver-plating has two functions: one is to prevent oxidation and rust, and the other is to facilitate welding. The plating quality of the stents It is very critical. It is related to the life of the LED. The treatment before electroplating should be carried out in strict accordance with the operating procedures. The processes such as rust removal, degreasing, and phosphating should be meticulous. The current should be controlled during electroplating, and the thickness of the silver plating layer should be controlled. If the coating is too thick, the cost is high, and too thin will affect the quality. Because the general LED packaging companies do not have the ability to inspect the plating quality of the bracket row, this gives some electroplating companies the opportunity to make the silver plating layer of the electroplated bracket row thin and reduce the cost. Insufficient inspection means, no instrument to detect the thickness and fastness of the plating layer of the bracket row, so it is easier to get confused. Even the packaged LED will have weak adhesion due to the thin silver-plated layer, and the solder joints will be separated from the bracket, resulting in dead lights. This is what we encountered when the light did not turn on when it was used properly. In fact, the internal solder joints were detached from the bracket.
Therefore, it is very important to choose a strong SMD LED lamp bead packaging company to expand the long-term cooperative relationship between Optoelectronics, Epistar and Cree, and 10 years of experience in low-power LED lamp T bead packaging.
