Identify virtual welding method of death lamp( Last but Impotant )
The lightless LED wire will be heated to lead 200-300 ℃ with lighter,remove the lighter,connect the LED with 3 v button cell according to the positive and negative , if the LED lamp can light up, but along with the wire temperature drop and the LED lamp change to not bright, it is proved that the LED lamp is virtual welding..The grounds of heating can light up is that by using the principle of the metal expand with heat and contract with cold, the heating LED wire elongate and connected with the internal welding point, then the power switch on, LED can be light normally. Temperature return to normal, and the internal welds disconnect, the LED is not light again.
Two wire of the virtual welding lamp are soldering in a metal bar,soaking with the concentrated sulfuric acid, and take out when dissolve LED external colloid competely, observe the welding condition of solder joints by the magnifying glass or microscope, you can find if it’s a welding or two welding problem, the parameters of gold ball welding set wrong, or other reasons, to improve the method and process, prevent virtual welding phenomenon happening again.
Using LED products users will encounter death light phenomena, when LED products to use after a period of time, death lamp occur,. There are two reasons of dead lights, the road dead lamp is not good for welding quality, or the quality of the plate is defective. The increase of the leakage current of LED chip will also make the LED light not bright. Now many LED products do not add antistatic protection to reduce costs, so it is easy to be susceptible to electrostatic damage. It is easy to have power line induction high voltage static electricity, and superimposed peak pulse of power lines, which will cause the LED products to suffer different degrees of damage.
In short,there are many reasons for the death lamp occurred cannot enumerated. Encapsulation, application, each use link will likely have die lamp phenomenon, how to improve the quality of the LED products, is the packaging and applying enterprises should attach great importance to and seriously study. From chip, support, to LED packaging, the whole process should be in accordance with ISO2000. Only in this way, the quality of LED products can be improved comprehensively,achieve long life and high reliability target. On the circuit design of the application, select the varistor and PPTC components to protection circuit perfectly, increase parallel, using constant current switching power supply, add temperature protection are effective measures to enhance the reliability of LED products. As long as the packaging and application enterprises are strictly in accordance with the ISO 2000 quality system, it will be able to bring the quality of LED products to a new level.