Patent ID: 7994871

Claim:
A chip on film (COF) trace routing method for electrical magnetic interference (EMI) reduction, comprising: providing a flexible circuit board; mounting a chip on the flexible circuit board, wherein the chip has a first signal pad, a second signal pad and a ground pad; forming a first signal trace on the flexible circuit board, wherein the first signal trace is electrically connected to the first signal pad for transmitting a first signal; forming a second signal trace on the flexible circuit board, wherein the second signal trace is electrically connected to the second signal pad for transmitting a second signal; forming a first ground trace on the flexible circuit board, wherein the first ground trace is electrically connected to the ground pad and is immediately adjacent to the first signal trace for EMI reduction; and forming a second ground trace on the flexible circuit board, wherein the second ground trace is electrically connected to the ground pad and is immediately adjacent to the second signal trace for EMI reduction; wherein the first signal trace and the second signal trace are disposed between the first ground trace and the second ground trace; the first ground trace and the second ground trace are symmetric with respect to each other; and the first signal trace is immediately adjacent to the second signal trace; the first signal trace is parallel with the first ground trace, the second signal trace is parallel with the second ground trace, and an interval between the first signal trace and the first ground trace is as wide as an interval between the second signal trace and the second ground trace.