Why do printed circuit boards have various colors?

In daily life, most PCBs are green, but sometimes, in addition to green, we can see blue, or even black PCBs. Why on earth do PCB boards choose different colors? Why is green the most common color? This paper will reveal the secret of "colorful" printed circuit board.

Green ink is by far the most widely used ink with the longest history. It is also the cheapest ink in today's market. Therefore, many manufacturers take green ink as the main color of their products.

Generally speaking, the whole PCB products have to go through board making, SMT and other processes in the production process. When making boards, there are several processes to pass through the yellow light room, and the effect of green must be better than that of other colors. However, when SMT is used as a welding element, PCB should go through the process of applying solder paste and patch, and finally AOI calibration lamp. In these processes, optical positioning calibration should be used. The green background has a good recognition effect on the instrument.

Common PCB colors are red, yellow, green, blue and black. But now, due to many problems such as production technology, the quality inspection process of many lines still depends on workers' visual observation and recognition or the use of flying needle detection technology. Because green is relatively the least harmful to the eyes in strong light, most manufacturers on the market use green PCB at present.

Moreover, both blue and black are doped with cobalt, carbon and other elements respectively, which have certain conductivity and are prone to short circuit problems when energized. Green PCB is relatively environment-friendly, and generally will not release any toxic gas when used in high-temperature environment.

Moreover, a few manufacturers in the market will use black PCB boards. This problem is mainly because black looks "higher", but the wiring in the blackboard is difficult to see, so it brings some difficulty to copy the board. At present, most Android embedded boards use black PCB.

In fact, the industry has begun to pay attention to the color of PCB boards since the middle and late last century. Because many high-end board types in front-line factories adopt green PCB color design, people gradually think that green is the "default" color of PCB.

The choice of printed circuit board color is the epitome of the rise, development and choice of an emerging technology in the development of modern science and technology. The birth and development of printed circuit boards are constantly evolving and changing in the countless processes that promote the electronic industry. Maybe in the near future, there will be other colors of PCB to replace the current trend of environmental protection. Let's wait and see!