Overview flexible PCB

The basic PCB is generally composed of components on one side, wires on the other side and wiring on one side. Therefore, this kind of PCB is called single panel. The double-sided board can be wired on both sides, so the wiring area will be twice as large as that of a single panel, which is suitable for more complex circuits.

Radio is a simple circuit. It can be made of single panel or double-sided board. However, with the development of microelectronics technology, the complexity of the circuit is greatly improved, and higher requirements are put forward for the electrical performance of PCB. The use of single panel and double-sided board has large circuit volume, wiring is also very difficult, and the electromagnetic interference between lines is also very difficult to deal with. Therefore, multilayer board appears (the number of layers represents several independent wiring layers, usually even). Generally speaking, the PCB boards of many companies are green because the green process is mature and simple. However, in extreme cases, there will be red, white, blue, yellow and matte. In more extreme cases, there are black, purple, chrysanthemum, bright green, etc. Normally, white products must be used for white printed circuit boards. Other colors are mostly product grading systems. Every company is different. Printed circuit boards are processed, and the colors of coatings are also different. Some use red to represent the experimental board, some use blue to represent the key board, and some use black to represent the board used inside the computer. Each has its own rules, which are not detailed. High quality substrate production is closely related to years of accumulated production experience. Substrate production enterprises have created high popularity and influence and accumulated relatively fixed consumer groups.

Here are the characteristics and advantages of multi-layer board:

The assembly density is high, the volume is small, and the connection between electronic components is shortened, which improves the signal transmission speed; Wiring is more convenient; The ground layer is added to the high-frequency circuit, and the signal line forms a certain low impedance to the ground, with good shielding effect. However, the more layers, the higher the cost, the longer the processing cycle, and the more troublesome the quality inspection.

When the FPC flexible circuit board has the problem of guidance / short circuit, the effective method is to check whether the circuit is broken under the optical microscope. It can be seen from the electronic and optical mechanical equipment that the circuit can not be detected under the optical microscope only after many examples have been encountered in the work, In fact, there is no need to be surprised by this result in the area where the golden finger is measured immediately in the three-purpose meter, because FPC is called flexible circuit board, because it is flexible and can be bent, which is also the advantages and disadvantages of FPC. The disadvantage is that it can be bent because it may lead to the fracture of copper foil circuit. Flexible PCB substrate company has domestic advanced production and testing equipment and experience, and has a rich management team.

Our common computer boards usually use four or six layer boards, but now there are more than 100 layers of practical printed boards. The difference between the six layer board and the four layer board is that two internal signal layers are added between the ground wire layer and the power layer, which is thicker than the four layer board.

Multilayer board is actually formed by laminating and bonding several etched single or double boards. The double-sided board is easy to distinguish and faces the lighting. In addition to the double-sided wiring, other places are transparent. For the four layer board and the six layer board, because the layers in the PCB are closely combined, if there are corresponding marks on the board, there is no good method to distinguish them. Perforation design is an important factor, which is composed of perforation, pad area around perforation and power layer isolation area. It is usually divided into blind hole, buried hole and perforation. In the process of PCB design, through the analysis of parasitic capacitors and parasitic inductors of vias, the matters needing attention in the design of high-speed PCB vias are summarized. The size of pad and perforation decreases gradually, but the thickness of plate layer does not decrease proportionally, the perforation aspect ratio increases, the perforation aspect ratio increases, and the reliability decreases. With the maturity of advanced laser punching technology and plasma dry etching technology, non perforated small blind holes and small buried holes can be applied. If the diameter of these non perforated holes is 0.3mm and the parasitic parameters are about 1 / 10 of the original common holes, it is conducive to improve the reliability of PCB.

The manufacturing process of PCB board begins with the printed circuit board substrate made of glass epoxy resin or similar materials. The first step is to draw the on-line wiring between light drawing parts. The method is to print the designed PCB substrate on the metal conductor.