Today Ledo will briefly explain what is flip COB LED chip.
Flip COB is the most recent trends in LED manufacturing and packaging. This LED has better thermal performance and allow higher power than standard SMD package.
What is Flip COB LED chip?
- COB: Chip on Board
COB is a new technology of LED packaging for LED light engine. Multi LED chips are packaged together as one lighting module. When it light up, it looks like a lighting panel.
What is the difference between traditional COB chip and flip COB chip?
(a) and 1(b) respectively show the schematic diagrams of a traditional wire-bond COB Chip and no wire-bond flip COB chip. In Figure 1(a), a traditional COB chip is bonded on the MCPCB substrate by bonding epoxy and connects to the circuit electrodes via two bonding wires. The thermal energy generated by the LED chip is dissipated through the chips’ sapphire substrate, bonding epoxy, followed by a MCPCB dielectric layer before reaching the metal core. On the other hand, the flip COB chip shown in Figure 1(b) has the LED chip directly bonded on the circuit electrodes without the bonding wire and epoxy. The heat generated by the LED is coupled through the chip bonding pads, circuit electrodes, MCPCB dielectric layer, and then diffused into the metal core. In comparison, the flip COB chip exhibits less thermal resistance as its thermal dissipating path excludes the sapphire substrate and bonding epoxy that are materials having higher thermal resistance.
Thermal decay is a natural characteristic for LED, as the optical output decreases when the LED junction temperature is increased. Therefore, the lighting efficacy would decrease following the increase of the LED junction temperature. In order to minimize the thermal decay, lowering the thermal resistance becomes essential to maintain or lower the LED junction temperature while more optical output is demanded through the increase of driving current.
Because Flip COB chip exhibit less thermal resistance, it can work under high current, this is important to apply to automotive led industry. While led bulb has high wattage, it can fit to more cars and computer won’t show error.。
Traditional COB chip connects to the circuit electrodes via two bonding wires, these bonding wires is possible to break during package or using. Flip COB chip don’t need these bonding wires, removing a potential risk and reducing the defective rate.