How much do you know about single and double-sided circuit boards?

- Jan 08, 2020-

How much do you know about single and double-sided circuit boards?

   Abstract: single sided printed circuit board is a product developed in the early 1950s with the emergence of transistors and centered on the United States. At that time, the main production method was direct etching of copper foil. From 1953 to 1955, the paper phenolic copper foil substrate was first made in Japan by using imported copper foil, and it was widely used in radio.

 

Single panel history:

 

  Single sided printed circuit board is a product developed in the early 1950s with the emergence of transistors and centered on the United States. At that time, the main production method was direct etching of copper foil. From 1953 to 1955, the paper phenolic copper foil substrate was first made in Japan by using imported copper foil, and it was widely used in radio. In 1956, after the emergence of Japanese circuit board manufacturers, the manufacturing technology of single panel made rapid progress.

 

   In terms of materials, the paper-based phenolic copper foil base plate was mainly used in the early stage. However, due to the factors such as low electrical insulation, poor welding heat resistance and distortion of phenolic material at that time, paper-based epoxy resin and glass fiber epoxy resin were developed successively. At present, the single-sided board required by consumer electronic machines almost uses paper-based phenolic base plate.

 

Features of single panel:

 

   The single panel is on the most basic PCB, with parts on one side and wires on the other. Because wires only appear on one side, we call this kind of PCB a single side. Because there are many strict restrictions on the design circuit of single panel (because there is only one side, the wiring can't cross and it has to go around its own path), only the early circuit can use this kind of board;

 

    The wiring diagram of single panel is mainly screen printing, that is to say, resistance agent is printed on the copper surface, then marks are printed on the anti welding resistance after etching, and finally the part guide hole and shape are completed by punching. In addition, some of the products produced in a small number and in a variety of ways adopt the photographic method of forming patterns with photoresists.

 

Double side circuit board

 

   Double sided boards have wiring on both sides. However, to use two-sided wires, there must be a proper circuit connection between the two sides. The "bridge" between these circuits is called the vias. The guide hole is a small hole filled or coated with metal on the PCB, which can be connected with the wires on both sides. Because the area of the double-sided board is twice larger than that of the single panel, and because the wiring can be interleaved (can be wound to the other side), it is more suitable for circuits more complex than the single panel.

 

   In a strict sense, the double-sided board is a very important PCB in the circuit board. Its purpose is very big. It's also very simple to see whether a PCB is a double-sided board. I believe that friends can fully grasp the understanding of the single panel. The double panel is the extension of the single panel, which means that the circuit of the single panel is not enough to turn to the opposite side. The double-sided board also has the important feature of Through hole. Simply speaking, it's double-sided. There are lines on both sides! An exclamation is: double-sided board is double-sided board! Some friends will ask, for example, if a board has two-sided wiring, but only one side has electronic parts. Is such a board a double-sided board or a single panel? The answer is obvious. Such a board is a double-sided board, only the parts are installed on the board of the double-sided board.

 

Simple differentiation of multilayer circuit board

 

  The circuit board determines the process difficulty and processing price according to the number of wiring surfaces. The common circuit board is divided into single-sided wiring and double-sided wiring, commonly known as single panel and double-sided board. However, due to the constraints of product space design, in addition to surface wiring, multiple layers of wiring can be superimposed inside. During the production process, after each layer of wiring is made, it is positioned and pressed by optical equipment Close, let the multi-layer circuit stack in one circuit board. Commonly known as multilayer circuit board. Any circuit board greater than or equal to 2 layers can be called multilayer circuit board. Multilayer circuit board can be divided into multilayer hard circuit board, multilayer soft hard circuit board and multilayer soft hard combined circuit board.

 

The birth of multilayer circuit board

 

   Due to the increase of IC package density, the interconnect is highly concentrated, which makes the use of multiple substrates necessary. In the layout of printed circuit, unforeseen design problems appear, such as noise, stray capacitance, crosstalk and so on. Therefore, PCB design must be committed to minimizing the length of signal lines and avoiding parallel routes.

 

   Obviously, in the single panel, even in the double-sided panel, due to the limited number of intersections that can be realized, these requirements can not be satisfied. In the case of a large number of interconnection and cross requirements, if the circuit board wants to achieve a satisfactory performance, it must expand the board layer to more than two layers, so there are multi-layer circuit boards.

 

   Therefore, the original intention of manufacturing multilayer circuit board is to provide more freedom for complex and / or noise sensitive electronic circuits to choose the appropriate routing path. The multilayer circuit board has at least three conductive layers, two of which are on the outer surface, and the remaining one is synthesized in the insulating board. The electrical connection between them is usually realized by plated through holes on the cross section of the circuit board. Unless otherwise stated, multilayer printed circuit board and double-sided board are generally plated through-hole board.

The use of multi substrate is in the professional electronic equipment (computer, military equipment), especially in the case of weight and volume overload. However, this can only be achieved by increasing the cost of multiple substrates in exchange for increasing space and reducing weight. In high-speed circuits, multi substrates are also very useful. They can provide more than two layers of board surface for PCB designers to lay wires, and provide large grounding and power areas.

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