In electronic devices, ranging from small electronic watches and calculators to computers, general electronic devices, and military weapon systems, as long as there are electronic components, their interconnections use PCBs. The printed circuit board (PCB) is one of the important components of electronic products. The main function of the PCB is to provide mechanical support for the fixed assembly of various components, realize wiring, electrical connections, and electrical insulation between electronic components. The quality of the printed circuit board directly affects the performance of electronic products, and the quality of the printed circuit board is determined by both design and manufacturing. Below we will introduce the types of copper-clad laminates. There are many types of copper-clad laminates, classified by reinforcement materials into paper-based boards, glass cloth boards, and synthetic fiber boards; classified by structure into single-sided printed circuit boards, double-sided printed circuit boards, multilayer printed circuit boards, flexible printed circuit boards, and flat printed circuit boards; classified by adhesive resin into phenolic, epoxy, polyester, and polytetrafluoroethylene copper-clad laminates, etc. Below we will introduce single-sided printed circuit boards, double-sided printed circuit boards, multilayer printed circuit boards, flexible printed circuit boards, and flat printed circuit boards according to their structural classification.
Single-Sided Printed Circuit Board A single-sided printed circuit board has printed conductors on only one side of the insulating substrate. It is made from a single-sided copper-clad laminate processed from phenolic paper, epoxy glass cloth, or phenolic glass cloth, mainly used in applications with low electrical performance requirements such as radios, televisions, and instruments. Double-Sided Printed Circuit Board A printed board with conductors printed on both sides of the insulating substrate is called a double-sided printed circuit board. It generally uses metallized holes (holes with a metal layer plated on the wall, also known as vias) to connect the conductors on both sides. The double-sided printed circuit board is made from double-sided epoxy glass cloth or epoxy phenolic glass cloth as the substrate. This type of circuit board is mainly used in electronic computers, electronic switches, and other information communication electronic devices. Multilayer Printed Circuit Board A printed circuit board made with three or more layers of printed circuits on the insulating substrate is called a multilayer printed circuit board. It is formed by bonding several thinner single-sided or double-sided boards together, connecting the printed conductors between layers through metal vias. The characteristics of multilayer printed circuit boards include: high wiring density, in line with the trend of miniaturization and lightweight of electronic products, and can improve electrical performance, for example: by shortening the length of printed lines, reducing circuit delay time, and mutual shielding between layers, enhancing circuit stability, etc.
Flexible Printed Circuit Board A flexible printed circuit board is made from flexible materials such as polyimide and polytetrafluoroethylene film as the substrate, thermally pressed with copper foil, and can be single-layer, double-layer, or multilayer flexible printed circuit boards. Its characteristics include: small size, lightweight, can be bent and folded, allowing full utilization of internal space in electronic products, and making maintenance work more convenient. Flexible printed circuit boards are widely used in communication equipment, electronic calculators, instruments, and electronic products in military science and the automotive industry.
Flat Printed Circuit Board The printed conductors of a flat printed circuit board are embedded in the insulating substrate, flush with the surface of the substrate, and are usually used in toggle switches, automatic communication machines, and computer keyboards, as well as in analog/digital and digital/analog converters. The printed circuit board is a key component that connects discrete electronic components together, and its quality directly affects the performance of electronic products. From the manufacturing process perspective, the wiring density should be minimized to reduce interference between lines and lower the manufacturing difficulty of printed circuit boards. From an economic perspective, standard specifications of materials should be selected as much as possible to facilitate mass production and reduce costs.
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