The existence of double giants in the field of LED display has jointly developed and flourished the LED industry. As a common but unfamiliar field in reality, today I will briefly introduce the definition of COB, SMD and the difference between COB and SMD.
What is the definition of COB?
COB is the abbreviation of chip on board, which means chip on board packaging. COB is one of the bare chip mounting technologies. Semiconductor chips are handed over and mounted on printed circuit boards, and the electrical connection between the chips and the base boards is realized by lead stitching. The electrical connection between the chip and the substrate is realized by suture method and covered with resin to ensure reliability. The method is to first cover the silicon wafer placement point with thermal conductive epoxy resin (generally silver-doped epoxy resin) on the base surface. Then the silicon wafer is placed directly on the surface of the substrate and heat treated until the silicon wafer is firmly fixed on the substrate. Then the electrical connection between the silicon wafer and the substrate is directly established by wire welding.
What is the definition of SMD?
Surface Mounted Devices, short for Surface Mounted Devices, It is one of SMT (Surface Mount Technology) components. "In the primary stage of the production of electronic circuit boards, through-hole assembly is completely completed manually. After the first batch of automation machines were introduced, they could place some simple pin components, but complex components still need to be manually placed before wave soldering can be carried out. Surface mount components (SMEs) were introduced about 20 years ago and ushered in a new era. From passive components to active components and integrated circuits, they eventually become surface mounted devices (SMDs) and can be assembled by pickup and playback devices. For a long time, it was believed that all pin components could eventually be packaged in SMD.
Differences between COB and SMD
1. Traditional SMD packaging, SMD packaging production efficiency is low, its wire efficiency is similar to traditional SMD, COB packaging efficiency is higher than traditional SMD.
2. Spotlight and glare exist in traditional SMD packaging discrete device combination; COB packaging has large angle of view and is easy to adjust, which reduces the light refraction loss.
3. Traditional SMD packages need to be patched first and then fixed on PCB board by reflow soldering. COB packaging does not require mounting and reflow soldering process. COB light source is directly applied to lamps and lanterns.