COB package Chips on board (Chips on Board, COB), is to solve the problem of LED cooling technology. Compared to the plug-in and SMD is characterized by space-saving, simplified packaging operations, with efficient thermal management.
COB package that is chip on board, is the bare chip with conductive or non-conductive adhesive attached to the interconnect substrate, and then wire bonding to achieve its electrical connection. If the bare chip is exposed directly to the air, is susceptible to contamination or artificially damaged, it affects or destroys the chip function, so the chip and the bonding wire are encapsulated with glue. It is also called this package in the form of soft encapsulation.
Nearly two years of LED market and technology continues to develop and change, COB has become the main package of LED, in the increasingly demanding light efficiency today, the heat will be a big problem, and China LED, already began to layout.
Light efficiency requirements are getting higher and higher, will inevitably lead to increased power, thermal conductivity will become a rigid indicator, the rise of ceramic substrate, unstoppable
1: Compared with the traditional aluminum substrate, ceramic substrate reflectivity is high, help to improve the luminous efficiency.
2: ceramics with high reliability, long life and so on.
3: ceramic thermal expansion and contraction coefficient is small, even in high temperature environment, its surface is more flat, contribute to heat.
4: easy to assemble, you can Zenigata LED module through the thermal glue directly on the radiator.
5: ceramic thermal conductivity is high, which can ensure that SHARP Zenigata LED has the industry's leading heat lumen maintenance rate (95%)
6: ceramic for the insulator, LED lighting products through a variety of high-pressure test
At present, the domestic LED packaging market, the importance of ceramic packaging is getting higher and higher, then pick a good ceramic substrate is a very important issue. It is reported that the domestic ceramic substrate rankings, Sri Lanka ceramic circuit board among the best.
Laser Activation Metallization (LAM) technology, the use of high-energy laser beam ceramic and metal ions of the state, so that they are long together so that they firmly together. Sally Tong ceramic circuit board has the following advantages than the general ceramic substrate more prominent:
1. Higher thermal conductivity: the traditional aluminum-based circuit board MCPCB thermal conductivity is 1 ~ 2W / mk, copper thermal conductivity is 383.8W / m. K, but the thermal conductivity of the insulating layer is only 1.0 W / m. K. About a little better to achieve 1.8W / m. K. Thermal conductivity of alumina ceramic: 15 ~ 35 W / m. K, aluminum nitride ceramic thermal conductivity: 170 ~ 230 W / m. K, copper substrate thermal conductivity of 2W / (m * K), aluminum / copper-based circuit board: its own high thermal conductivity, but the aluminum / copper-based circuit board insulation layer, resulting in the whole board thermal conductivity decreased The We can use ceramic base instead of insulation, aluminum / copper as the substrate, ceramic-based insulation.
2. More matching thermal expansion coefficient: the normal light when the temperature up to 80 ℃ ~ 90 ℃, the temperature can not withstand lead to welding is not strong. General lights are 0.1w, 0.3w, 0.5w, for 1w, 3w, 5w, the lights, PVC can not bear. Ceramic and chip thermal expansion coefficient close to the temperature difference will not produce too much deformation caused by line desoldering, internal stress and other issues!
3. The metal layer has a high bonding strength to the ceramic substrate, and can reach a maximum of 45 MPa (greater than 1 mm thick ceramic sheet itself). The conductivity of the metal layer is good, for example, the resulting copper The volume resistivity is less than 2.5 × 10-6Ω. Cm, when the current through the small heat.
In the era of COB large-scale innovation, the ceramic substrate is unstoppable, and the core technology of the Slighty ceramic circuit board, will be in the field of LED packaging shine.