With the rapid development of display technology, COB packaging products have become a hot spot in the mid-to-high-end display market and become the development trend of display screens in the future. What is COB? Today, let the editor introduce in detail:
1. LED display technology
At present, there are two main forms of small-pitch full-color LED display packaging technology, one is the surface mount component SMD technology, which uses COB technology to integrate packaging. Surface mount was introduced about twenty years ago. From passive to active components and integrated circuit components, it eventually became a surface mount component (COB) and can be assembled by pick-and-place equipment. The COB is a large-scale application in a new packaging technology for full-color LED screens only in recent years.
SMD packaging technology
SMD: is the abbreviation of surface mount equipment, which means surface mount equipment. It is one of SMT (Surface Mount Technology) components. At present, indoor full-color LED displays mainly use three-in-one surface-mounted SMD, which refers to SMT lamps packaged with three different colors of RGB LED chips, according to a certain distance Encapsulation in the same gel to form the packaging technology of the display module.
The main process is to encapsulate the LED light-emitting chip in the bracket to form lamp beads (SMD surface mount), and then paste it on the PCB board through solder. Then put the surface mount and PCB board in a high-temperature oven for sintering and curing (reflow soldering), and then solder the LED leads through a pressure soldering process, then glue the bracket with epoxy resin, and finally form the display module, and then splice the module to the unit middle.
The core material of SMD process:
Stand: Conductive support and heat dissipation, the support material is electroplated to form multiple, from the inside to the outside is the material, copper, nickel, copper, silver, five layers.
LED chip: The chip is the main component of the LED lamp and is a light-emitting semiconductor material.
Conductive circuit: PAD chip connection (PAD) and bracket, and can be rotated.
Epoxy resin: protects the internal structure of the lamp beads, and can slightly change the color, brightness and angle of the lamp beads;
2. COB packaging technology
COB: Abbreviation for chip on board. Way: Chip-on-board technology; the chip is attached to the interconnection substrate with conductive or non-conductive adhesive, and then through the semiconductor packaging process of wire bonding, its electrical connection is achieved. In short, the light-emitting chip is directly mounted on the PCB, and the soldering feet do not need to be endured. Compared with the conventional practice SMD, the lamp beads are omitted, and two COB LED chip packages with reflow process are made. The chip is directly mounted on the PCB. Basically, there is no limit to the size of the packaging device that can be arranged with a small arrangement pitch. The current micro LED COB technology is used.
Compared with other packaging technologies, the process of cob technology is simpler, as shown in the following figure:
Led screen features of Cob packaging technology:
Super "stable": almost no failures, no dead spots.
1. Super "stability": almost no faults and no dead spots.
2. Not "dazzling": Use surface light sources instead of "dazzling" point light sources and other environmental protection technologies. The brightness is soft and protects human eyes.
3. Not "squeaky": not afraid of bumps, can be wiped with water, protection grade IP66.
4. No "seam": you can "customize" precision displays of different scales.
5. Use "long life": 24 hours and 365 days of continuous use for more than 8 years (theoretical 10 years).
6. "It is the future": It will replace DLP, LCD, plasma, projection, movie screen, SMD LED display and other display products.
The distribution of physical spacing corresponding to different packaging processes of LED display
The physical space distribution corresponding to different packaging technologies of LED display
In the future, the LED display pitch can be infinitely small, which is a display technology based on COB packaging technology.
