East guide science and technology on the history of the copy board Series 9: PCB 【PCB copy board】
Update date：2012-6-26
This chapter will introduce the knowledge of the relevant PCB, PCB (Printed Circuit Board) Chinese name for the printed circuit board, also known as printed circuit board, is one of the important components of electronic products. Almost every electronic equipment, electronic watches, calculators, large electronic devices to the computer, communications, military
Weapons systems, electronic components, electrical interconnection between them is necessary to use a printed circuit board. In the large electronics product development process, one of the most fundamental factors affect the success of electronic products is the PCB design and manufacturing of the product.
PCB design and manufacture of quality directly affects the quality and cost of the entire electronic product, and even affect the competitiveness of electronic products in the market competition.
Early in the development of electronic technology, the components are connected by wires, components fixed three-dimensional space. The circuit consists of power supply, wires, switches and components, like electrical experiments in the laboratory circuit. With the development of electronic technology, electronic products, functions, structure becomes very complex, component layout, interconnection wiring is not as casually as before, or check will be dazzled. Therefore, the components and circuit planning.
Sided Bonded Copper invention, a circuit board design and create a new sign of the times. Wiring design and production techniques have been developed. Bonded Copper on the first template printing anti-corrosion film map, and then corrosion groove, this technique is like printing is so easy on paper, printed circuit board, hence the name, English Print Circuit Board, referred to the PCB. The printed circuit board applications significantly reduce the cost of production, from the transistor era to the present, this single-sided printed circuit board has been widely used. With the advances in technology, invented the double sided copper board on both sides, both sides of the corrosion can be engraved line.
Because of the complexity of the circuit, and sometimes used the fly line. Circuit wiring is not the components according to circuit theory is simple to connect can be the circuit is electromagnetic induction, the resistance effect, capacitance effects will affect the performance of the circuit, and even cause serious quality problems, such as self-excited, the signal is incomplete transmission electromagnetic interference and other issues. The fly line method can only solve a small amount of signal interlacing problems, too many is not desirable. Which insists that all lines are ranked in the limited on both sides, but also to reduce the electromagnetic induction, the resistance effect, capacitance effects, making the wiring design of a very difficult task. The lines are too small and too close, not only the processing difficulties, interference, and easily blown circuit fault occurs. To ensure the line width and spacing, board size may be too large, is not conducive to the miniaturization of precision equipment. These problems prompted the development of the printed circuit board design and production process.
With the development of electronic product manufacturing technology, development of sandwich on the basis of double-sided circuit board, in fact, is superimposed on the double-sided on the basis of a single panel, which is multi-layer circuit board. At first, mezzanine and more with a bigger area of the ground, the wiring of the power cord to the surface are used for signal routing. Later, mezzanine used for signal wiring more and more, which makes the circuit board layers will also increase. But the sandwich can not be infinitely increased, mainly due to cost and thickness. The general production plant to obtain the highest possible performance at the lowest possible cost, which is done in the laboratory prototype machine design.
Therefore, the electronic product designers to take into account the cost of this conflict complex, the most practical design method is still based on the surface do the signal wiring layer is preferred. The high frequency circuit components can not row too close, otherwise the component itself, the radiation will directly interfere with the other components. The wiring between layers should be staggered into a cross direction, in order to reduce wiring capacitance and inductance.
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