Technology | LED static failure principle and detection method（2）

1,624 views admin 2020-04-13

Good antistatic index is a reliable and comprehensive reflection of LED comprehensive performance

The antistatic index of LED will never simply reflect the antistatic strength. Anyone who understands the epitaxial design and manufacture of LED chips understands that the antistatic ability of LED chips is accompanied by leakage value. The comprehensive manifestation of comprehensive quality and reliability, because LEDs with high antistatic capability often have good optical and electrical properties.

The good antistatic index of LED not only means that it can be applied to various products and various environments, but also a reliable embodiment of LED's comprehensive performance. According to the LED anti-static indicators of different brands, the LED anti-static of various international LED manufacturers are usually better, while the anti-static of some B-brand, miscellaneous brand, Korean chips is still very low. The level of LED antistatic capability is the core embodiment of LED reliability. Even if the LED's brightness and electrical indicators are very good, once its antistatic index is low, it is easy to die due to electrostatic damage.

Enterprises familiar with LED manufacturing are well aware of the current uneven quality of products in the Chinese LED industry. The stability of LEDs of different qualities is very different, making many LED users confused and even suffering.

Among them, quality accidents such as dimming, dead lights, and leakage caused by low LED anti-static are the most severely lost. In particular, there are some inferior products of low quality and chips from Korean companies and Korean companies are pouring in, even if they are Large-scale products and middle-level sellers often appear to be sub-charged, and many companies face huge risks. Experts in the industry believe that as long as LED packaging companies choose LED chips with higher static resistance capability and do a good job in packaging, the products will be reliable and stable.

LED anti-static

Detection method

Many companies evaluate the antistatic properties of LEDs by "trying a batch to see the consequences". In fact, this is an evaluation method with long period, large error, high cost and high risk.

Electrostatic breakdown of LED is a very complicated process. During the LED antistatic test, static electricity must be directly applied to the two pins of the LED. The discharge waveform of the instrument has strict standards. Among them, human body model and mechanical model are both used to measure the antistatic ability of the measured object.

Human body mode: When static electricity is applied to the measured object, a 330 ohm resistor is applied in series. This is the charge transfer when simulating the contact between the human and the device. The human-object contact usually also acts at 330 ohm, so it is called the human body mode.

Mechanical mode: the static electricity directly acts on the device under test, and the simulation tool machinery directly transfers the electrostatic charge to the device, so it is called the mechanical mode.

The energy storage and discharge waveforms of the electrostatic charge inside the two test instruments are also somewhat different. The results of the human body model test are generally 8-10 times that of the mechanical model. The LED industry, and many companies now use human body indicators.