With the rapid development of modern science and technology, the application field of LED lamp beads has become more and more extensive. At the same time, the number of LED brands and models on the market has also gradually increased, which is mixed with a large number of low-quality LED lamp beads. Next, we will analyze the bad conditions of these low-quality LED bulbs and the causes.

LED

1： Dead light (the light does not light up or slightly lights up when the positive and negative poles of LED are connected to the standard voltage). There are many complicated reasons for dead light, mainly from the perspective of static electricity and packaging.

2： Color deviation (it means that the white light emitted by the LED has an error with the standard color temperature, and the error value is more than 10%), which is due to poor heat dissipation, which makes the junction temperature of the LED lamp beads too high; The application of fluorescent powder is uneven, and the color temperature of the thick coating part is low, which is prone to yellowing; Poor quality of phosphor; Improper mixing of rubber powder, etc.

3： The light flashes (the LED light turns on and off intermittently when it is not under human control), which is caused by the unstable driving power supply and intermittent current; In addition, the lens and other packaging materials are deformed by force, resulting in poor contact of gold wire.

4： The light attenuation is large (after the LED is used for a certain period of time, the measured luminous flux is significantly less than that before use, and the ratio of the two is less than 0.9), which is caused by poor heat dissipation and LED lamp beads aging due to prolonged overheating; Improper rubber powder ratio.

5： Chip failure, chip quality problem (crack or damage); Poor adhesion between chip and substrate causes serious light failure or dead light.

6： Improper packaging process, poor quality of encapsulated lamp beads, yellowing, bubbles, black spots, corrosion and other phenomena; Thermal overstress failure and poor heat dissipation cause junction temperature rise; Electric overstress failure, over-current or static electricity will break down the chip; The unstable drive power will burn out the gold wire. Assembly failure, poor installation and assembly lead to device failure.