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Introduction of the COB

Blaze Display Technology Co., Ltd. | Updated: Nov 27, 2018

Chip on board (COB) is a method of circuit board manufacturing in which the integrated circuits (e.g. microprocessors) are wired, bonded directly to a printed circuit board, and covered by a blob of epoxy.

By eliminating the packaging of individual semiconductor devices, the completed product can be more compact, lighter, and less costly. In some cases, COB construction improves the operation of radio frequency systems by reducing the inductance and capacitance of integrated circuit leads.

COBs containing arrays of light-emitting diodes have made LED lighting more efficient. LED COBs include a layer of silicone containing yellow Ce:YAG phosphor that encapsulates the LEDs and turns the blue light of the LEDs into white light. They could be compared with multi chip modules or hybrid integrated circuits since all three can incorporate multiple dies into a single unit. PCB with glop-top COB Chips on board is widely used in electronics and computing.

Chip-on-Board or "COB" is the latest and most advanced LED technology on the market today. Simply put, our COB LEDs are brighter, consume less power, and output a higher quality beam of light compared to older LED technologies, such as "SMD" or "DIP" LEDs.

How COB work?

A finished semiconductor wafer is cut into dies. Each die is then physically bonded to the PCB. Three different methods are used to connect the terminal pads of the integrated circuit (or other semiconductor device) with the conductive traces of the printed circuit board. 

In "flip chip on board", the device is inverted, with the top layer of metallization facing the circuit board. Small balls of solder are placed on the circuit board traces where connections to the chip are required. The chip and board are passed through a reflow soldering process to make the electrical connections.

In "wire bonding", the chip is attached to the board with an adhesive. Each pad on the device is connected with a fine wire lead that is welded to the pad and to the circuit board. This is similar to the way that an integrated circuit is connected to its lead frame, but instead the chip is wire-bonded directly to the circuit board. 

In "tape-automated bonding", thin flat metal tape leads are attached to the device pads, then welded to the printed circuit board.  In all cases, the chip and connections are covered with an encapsulant to reduce entry of moisture or corrosive gases to the chip, to protect the wire bonds or tape leads from physical damage, and to help dissipate heat.

There are some advantages over COB displays.

(1)Strong heat dissipation: COB products are packaged on the PCB board, and the heat of the wick is quickly transmitted through the copper foil on the PCB board, and the thickness of the copper foil of the PCB board has strict technical requirements, plus sinking The gold process hardly causes severe light attenuation.

2COB products directly encapsulate the LED chip in the concave lamp position of the PCB board, and then encapsulate it with epoxy resin. The surface of the lamp point is convex into a spherical surface, smooth and hard, and resistant to impact. mill.

There are many other advantages and more detail of COB technology. If you want to learn more about the advantages and detail, view on this website.www.blazedisplay.com.

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