Seven common causes of dead led beads
Time:2018-11-29
Views:132
Led screens often encounter dead lights. As a well-known enterprise in the led industry, delenser analyzes seven reasons why led beads die lights:
First, led lamp internal connection wire solder joint short circuit caused by the phenomenon of dead light.
Second, static electricity causes damage to led chip, which makes PN junction of led chip fail and leakage current increase into a resistance static electricity will be a hazard. There are countless electronic components damaged by static electricity all over the world, causing tens of millions of dollars of economic losses.Therefore, to prevent electrostatic damage to electronic components, is a very important work in the electronic industry, led packaging, applications of enterprises must not take it lightly.Any problem in any link will cause damage to the led, making the led performance worse or even invalid.A good chip or led, if we use the hand directly to take, chip or led will be damaged to varying degrees, sometimes a good device after our hand is somehow broken, this is caused by static electricity.
The third, welding process is also very critical, the golden wire ball welding machine pressure, time, temperature, power four parameters should be appropriate, in addition to the time fixed, the other three parameters are adjustable, pressure regulation should be moderate, pressure is easy to crush the chip, too small is easy to virtual welding.Welding temperature adjustment for good in 280 ℃, generally refers to the regulation of power ultrasonic power regulation, have poor is too big, too small, with moderate degree, in a word, the adjustment of the gold ball welding parameters, with good welding material, spring torque tester is used to inspect or 6 grams, is qualified.Every day to the wire ball welding machine parameters for testing and correction, to ensure that the welding parameters in the best state.In addition, the arc of welding wire is also required. The arc of a single solder joint chip is 1.5-2 chip thickness, and that of a double solder joint chip is 2-3 chip thickness. The radian will also cause quality problems of led.
, generally USES encapsulation of led, 4 stents row is to use copper or iron by precision stamping die, metal materials as copper more expensive, the cost is high, affected by the market fierce competition, in order to reduce the manufacturing cost, market mostly about using cold rolled low carbon steel with stamping led stent, iron stent through silver, silver plated has two, one is to prevent oxidation rust, 2 it is convenient for welding, bracket plating quality is critical, it is related to the led life, should be dealt with in accordance with the procedures before plating, cleaning, degreasing, phosphating process should be conscientious and meticulous,Electroplating to control the current, silver coating thickness to control, coating is too thick cost is high, too thin affects the quality.Because general led packaging companies don‘t have the ability to test support platoon plating quality, it gives some electroplating enterprises exploit, make stent row of silver plating layer thinning, reduce costs, general packaging companies IQC for lack of support line inspection means, no detection stent coating thickness and the fastness of the instrument, so easy to muddle through.Even the encapsulated led may be too thin because of the silver coating adhesion is not strong, solder joint and bracket off, resulting in the phenomenon of dead light.So that‘s what we‘ve got here and it‘s working really well and the lights don‘t go on, it‘s just that the internal solder joint is off the bracket.
Fifth, some small businesses use manual welding, using 40-watt ordinary iron, the welding temperature control, solder iron temperature above 300-400 ℃, the welding of high temperature can cause death lamp, led lead expansion coefficient at high temperature is higher than about 150 ℃ the expansion coefficient of the several times, internal gold solder will because of excessive heat bilges cold shrink the welding points and death light phenomenon.
Sixth, packaging enterprise production process is not complete, raw material inspection means is backward, is the direct cause of led dead light.
Seventh, in the packaging process, each process must be carefully operated, any link negligence is the cause of the dead light.
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