The important components of the LED display are LED lamp beads and LED unit boards. If there is a problem with any of them, it will directly affect the overall quality of the LED display screen! Therefore, how to distinguish the quality of LED lamp beads and LED unit boards is The problems that LED display merchants are concerned about, the following is a common method for detecting the quality of LED lamp beads and PCB unit boards, hoping to help LED display merchants. In addition, quality is king, and it is also necessary for manufacturers to reject cheap and shoddy products and components, so as not to damage and affect normal work and subsequent unnecessary maintenance.

 LED unit board sheet. In order to compete at low prices, some LED unit board manufacturers use cheap flame retardant paper boards or single-sided fiberboards as PCB circuit boards for LED lights. Because all glass fiber PCB boards are expensive. No difference can be seen at the beginning. Under normal circumstances, it will break due to moisture, ultraviolet damage, oxidation and other reasons within a year, resulting in the scrapping of the entire LED unit board. High-quality LED unit boards must use double-sided full glass fiber PCB boards. Although the cost is high, the quality is guaranteed.

Observe whether the brands of IC devices used are consistent. What type of IC is used, and how many ICs are used, these are enough to affect the quality of the LED unit board. Some LED display manufacturers, in order to save costs, deliberately reduce the number of ICs when producing unit boards, or mix ICs of other brands.

Lamp beads and chips. The naked eye cannot distinguish the quality of the lamp beads. It can only rely on a long-term test, which is what experts call an aging test. The general practice of LED display manufacturers is to turn on the power before leaving the factory to check whether the LED display can operate normally, and it will not undergo a long-term aging test. Because it requires a lot of time cost and labor cost.

Welding quality: Check whether the patch has components missing or incorrectly attached, and whether there is a short circuit of component pin burrs. Check whether the solder joints of the straight plug-in are smooth and round, whether the board surface is clean and tidy, and there is no false soldering or missing soldering. Check the flatness of the light-emitting dot matrix and the consistency of the ink color.

Power-on test: power-on test the consistency of the light-emitting dot matrix; power-on test whether the line driver tube CEM4953 is effectively protected; power-on test signal transmission capability.

The main material components used in LED lamp bead packaging include brackets, chips, die-bonding glue, bonding wires and packaging glue. SMD (Surface Mounted Devices) refers to the surface mount package structure LED, mainly including PCB board structure LED (ChipLED) and PLCC structure LED (TOP LED). The following introduces some basic development status in China from the aspect of packaging materials.

The role of the stent. The PLCC (Plastic Leaded Chip Carrier) bracket is the carrier of the SMD LED device, which plays a key role in the reliability and light output of the LED. The PLCC bracket production process mainly includes metal strip punching, electroplating, PPA (polyphthalamide) injection molding, bending, five-sided three-dimensional inkjet and other processes. Among them, electroplating, metal substrates, plastic materials, etc. occupy the main cost of the stent. Structural improvements to the stent design. Because the PPA and the metal are combined physically, the PLCC bracket will have a larger gap after the reflow oven at a high temperature, which will cause moisture to easily enter the device along the metal channel and affect reliability.

In order to improve product reliability and meet the high-quality LED display devices required by the high-end market, some packaging factories have improved the structural design of the bracket, such as using advanced waterproof structure design, bending and stretching methods to extend the water vapor entry path of the bracket At the same time, multiple waterproof measures such as waterproof grooves, waterproof steps, and drainage holes are added inside the bracket.