The color of the PCB surface is actually the color of the solder resist. Solder resist one is to prevent the occurrence of wrong soldering of components,
The second is to delay the service life of the device and prevent oxidation and corrosion of the device circuit. If you know more about electronic products, you will find that the color of PCB is generally green. This is mainly because the green solder mask process is the most mature and simple, and the green board is also more environmentally friendly. In addition to green, PCB boards have white, yellow, red, blue, matte colors, and even chrysanthemum, purple, black, bright green, etc. White exists because it is a color that must be used to make lamps and lanterns, and the use of other colors is mostly to distinguish different product samples. During the entire stage of the company from R&D to product landing, depending on the different uses of the PCB, the experiment board may be purple, the key board will be red, and the boards inside the computer will be black, and they are marked by color. As for green oil, its solder mask ink is the oldest, cheapest and most popular. There are many advantages:
1. In PCB processing, the production of electronic products includes board making and post filming. During this period, there are several processes to pass through the yellow light room, and the green PCB board has the best visual effect in the yellow light room;
2. Secondly, during SMT patch processing, the steps of tinning, patching and AOI calibration all require optical positioning calibration, and the green bottom plate is more friendly when it is recognized by the instrument;
3. Part of the inspection process relies on worker observation (but now most use flying probe testing instead of manual labor), staring at the board under strong light, green is friendly to eyes;
4. Green PCBs are also relatively environmentally friendly, and no toxic gas will be released when the waste boards are recycled at high temperature.
Other PCB colors, such as blue and black, are doped with cobalt and carbon, respectively, because of their weak electrical conductivity and risk of short circuits. In addition, like black, purple, and blue lights, the color of the PCB substrate is too dark, which will increase the difficulty of the inspection and maintenance of the motherboard, and the process is not easy to control. Taking the black board as an example, the black board is most prone to problems in the production process and the ratio of raw materials. A little carelessness will cause obvious color difference and lead to a high PCB defect rate. The traces of the black circuit board are not easy to distinguish, which will increase the difficulty for later maintenance and debugging. Many PCB factories do not use black PCBs. Even in the fields of military industry and industrial control, products with extremely high quality requirements use green PCB substrates. The color of the PCB board does not affect its performance. In summary, it is not difficult for us to understand why the color of the circuit board PCB substrate is mainly green