The traditional LED light source (including COB) has a larger luminous surface, which is not easy to optimize the structural appearance of lamps. In this trend, with small light-emitting surface high-intensity beam output characteristics, gold-free packaging structure of high-density cob has become a large number of LED technology in the dazzling Nova, by the industry, then, the use of COB package technology has what advantages?
The cob is coming, the small spacing LED TV enters the new stage
What is cob (chip on board) small pitch display technology? That is, the LED light-emitting Crystal directly encapsulated on the PCB board, and the cell unit combined into a display technology. At present, Granville Chong, Sony and other industry giants of the technology gave strong support.
Domestic high-end large-screen display leading brand Wei Chuang believes that small spacing LED display can be divided into two stages: the first stage is to solve the problem of use, the core technology breakthrough manifests in the pixel spacing to reduce below 2 millimeters, P1.5 and P1.2 product mass production; the second phase of small spacing LED display is mainly to provide higher product reliability and visual experience effect, in which COB encapsulation is one of the most important technology directions.
COB PACKAGE Small spacing led why so magical
In the process of high-temperature operation, due to the different materials in the SMD patch package of LED lamp beads, such as copper stent, epoxy resin material and crystal thermal expansion coefficient, the heat stress change of lamp bead is unavoidable. This became the small spacing LED screen bad lights, dead lights of the core "culprit."
and the use of COB packaging technology, in the wafer after the packaging process, led crystal one-time to become the smallest cell display unit, no need to late two "table stickers" welding. This engineering process, through the reduction of a high precision and high temperature environment operation, the maximum degree of protection of the LED crystal electrical and semiconductor structure stability, can make the display of the bad lamp rate down to a magnitude or more.
Overall package, COB technology benefits a lot
Small spacing LED screen of the bad light and stability of the angle, in addition to reflow soldering "high temperature" damage process, there are several areas need to attach great importance to:
First, show the collision process of the unit. SMD products of the lamp bead is not with the PCB seamless connection, which makes the collision process easy to cause stress in a single lamp beads concentrated. And the large-screen system of transport, installation, and so on, there are inevitable vibration and collision. This resulted in a small spacing LED display bad light rate of "engineering" increase. COB encapsulation technology, through the epoxy resin, wafer, PCB board of highly integrated bonding molding, can effectively protect the chip and chip electrical connector parts stability.
Second, the temperature uniformity in the process of the system. The more spacing between the smaller SMD package small spacing products, the more the use of high-power small-particle led crystals. At the same time, the gap between the lamp bead and the display plate leads to the heat conduction ability obstacle during the wafer working. COB package Because of the use of a more integrated process, so that the crystal selection can choose the power area of lower density, crystal particles larger number of chips, and thus reduce the core luminous point of work intensity. At the same time, the cob package realizes the whole solid-state seamless heat dissipation under the epoxy resin, which makes the thermal concentration of LED crystals in working condition decrease, which can prolong the product life and enhance the stability of the system.
Third, the overall packaging process, cob to achieve "seal five prevention." That is, cob can be very good crystal, crystal electrical connection parts of the "waterproof, moisture-proof, dustproof, anti-static, oxidation-proof." Compared with SMD encapsulation, the long-term chemical and electrical stability damage of electrical connections occurs in the process, especially in the presence of vibrations and collisions-one of the culprits of persistent bad lights in long term applications.
As a whole, the cob package is a process that compares SMD products to provide "high reliability".