EN
The earliest use of printed circuit boards (PCBs) was paper-based copper-clad boards. Since the introduction of semiconductor transistors in the 1950s, the demand for PCBs has increased sharply. In particular, the rapid development and widespread use of integrated circuits have led to smaller electronic devices with higher circuit wiring density and difficulty, which require PCBs to be continuously updated. Currently, the variety of PCBs has developed from single-sided boards to double-sided, multilayer, and flexible boards; their structure and quality have also developed to ultra-high density, miniaturization, and high reliability; new design methods, materials, and processes for making PCBs constantly emerge. The current PCBs are mainly composed of circuits and graphics, dielectric layers, solder mask, silk screen, and surface treatment.
In terms of appearance, the color of the board printed circuit is usually green, but not limited to green, and this layer of color mainly depends on the color of the solder mask used in the solder resist layer. A layer of silk screen printing is also printed on the solder resist layer, usually with text and symbols to identify the location of the components.
When electronic devices use printed circuit boards, due to the consistency of the same type of printed circuit boards, errors in manual wiring can be avoided, and automatic installation or surface mount of electronic components, automatic soldering, and automatic testing can be achieved, ensuring the quality of electronic devices, improving labor productivity, reducing costs, and facilitating maintenance.
In terms of layers, PCBs are classified into single-sided, double-sided, and multilayer boards.
First, single-sided boards have components on one side and wire connections on the other. Because the wires only appear on one side, this type of PCB is called a single-sided board. Single-sided boards are usually simple to manufacture with low cost, but cannot be used in too complex products.
Double-sided boards are an extension of single-sided boards. When single-layer wiring cannot meet the needs of electronic products, double-sided boards are used. Both sides have copper traces, and the traces between the two layers can be connected through holes to form the required network connections.
Multilayer boards refer to printed boards with three or more conductive pattern layers and insulation layers laminated between them. Multilayer boards are the products of the development of electronic information technology towards high-speed, multi-function, large-capacity, small volume, thinness, and lightness.
In terms of characteristics, board printed circuits are classified as flexible boards (FPC), rigid boards (PCB), and flexible-rigid combination boards (FPCB).
