What is COF, COB structure in capacitive touch screen and resistive touch screen?

COF (Chip On FPC) will be integrated circuits (IC) fixed in the flexible circuit board on the grain of soft film assembly technology.

The use of flexible add-on circuit boards as a carrier for encapsulated chips to combine the chip with a flexible substrate circuit, or a single flexible add-on circuit board without encapsulated chips.

COB (Chip On Board) through the bonding of the IC die fixed on the printed circuit board, the process is the bare chip with adhesive tape directly on the PCB board in the specified position, through the welding machine with aluminum wire chip electrode and the corresponding PCB board pads connected up, and then use black glue to seal the chip and the aluminum wire curing, so as to achieve the chip and the board electrode of the electrical and mechanical connection between the electrodes. The process consists of seven processes: chip gluing, curing, pressure welding, testing, sealing, curing and testing.

COB process uses a small bare chip, equipment with high precision, used to process more lines, thin gaps, small area requirements of the PCB board, chip welding pressure with black curing sealing protection, so that the solder joints and weld lines are not subject to external damage, high reliability.

Reshine Display (HK) Technology Co., Limited, currently produces the main small-size standard capacitive touch screen is COF structure, large-size resistive touch screen standard product is COB structure. We can customize COF and COB according to customer's requirement. Contact us now-judy.zhang@reshine-display.com.