We turn on the universal computer's health panel to see a flexible thin film (flexible insulating substrate), printed on a silver white (silver paste) conductive graphics and healthy bit graphics. Because universal screen stencil method to get it, so we call this printed wiring board for flexible silver paste printed circuit board. And we go to computer city to see a variety of computer motherboard, graphics cards, network cards, modems, sound cards and home appliances on the printed circuit board is different. The substrate is made of paper (commonly used on the single) or glass cloth (commonly used in double-sided and multilayer), pre soaked phenolic or epoxy resin, surface side or stuck on the both sides of the copper clad book then laminated curing and radical. This circuit board is covered with copper sheets, and we call it a rigid plate. And then printed circuit board, we call it a rigid printed circuit board. Single sided printed circuit boards, printed circuit boards, printed circuit board, and then through the hole of the metal to form the printed circuit board, we call it double panel. If you use a piece of double sides as the inner layer, two pieces of one side or two sides of the outer layer or two pieces of double sides as the inner layer, two pieces of printed circuit board, through the positioning system and insulation bonding materials together and conductive graphics design requirements of the printed circuit board to become the four layer, six layer printed circuit board, also known as multilayer printed circuit board. Now more than 100 layers of practical printed circuit board.