Portable electronic device

A portable electronic device comprising:

• a printed circuit board having opposite first and second surfaces, said first surface being provided with at least one conductive pad;
• a flexible circuit board having inner and outer surfaces, a main part stacked on said second surface of said printed circuit board, and an extension part extending and folded from said main part and stacked on said first surface of said printed circuit board, said inner surface of said extension part facing said first surface of said printed circuit board and being provided with at least one conductive bump thereon, said outer surface of said main part being provided with at least one input key that is electrically coupled to said conductive bump, said conductive pad being bonded to said conductive bump;
• and
• an anisotropic conductive material bonded to said conductive pad and said conductive bump.