Green color is solder mask ink, which is mainly composed of resin, talcum powder and pigment. At present, the most famous ones in the market are Taiyo of Japan, South Asia resin of Taiwan, Changxing chemical industry of Taiwan, yongshengtai ink of Taiwan, etc. the price is generally 60-120 yuan / kg. Of course, there are other colors, such as red, yellow, black, etc. green is the most widely used.
About this question (why are most of the circuit boards green?) The answer to this question is as follows:
Viewpoint 1. Generally speaking, the whole electronic board level products have to go through the process of plate making and laminating. In the process of plate making, several processes have to go through the yellow light room. The visual effect of green in the yellow light room is better, but this is not the main one.
In SMT welding, we need to go through the tin and paste, as well as the final AOI calibration. In these processes, we need to learn the optical positioning calibration. The green background color is better for the recognition effect of the instrument.
Viewpoint 2. The common ones are red, yellow, green, blue and black. Due to the problem of technology, the inspection of many lines still depends on the eyes of workers (of course, most of them are tested with flying needles now). It’s a very tiring job to keep looking at the board with bright eyes. Green is relatively the most eye friendly.
So most of them are green.
Viewpoint 3. Blue and black are mixed with cobalt and carbon respectively, which have certain conductivity, so there is a risk of short circuit. Green PCB is more environmentally friendly, and it will not release toxic gases when used in high temperature environment.
Viewpoint 4. From about 2007, people began to pay attention to the color of PCB. The main reason is that the high-end boards of ASUS MSI and other first-line large factories all adopt the black PCB color design, so people gradually think that if the PCB color is black, it must be high-end. After that, more and more manufacturers began to use black PCB coating – it can be said that an inexplicable reason caused such an inexplicable phenomenon. No one has ever said that if the PCB color is black, it means that the quality of the motherboard must be good. This is completely because the first-line brands use black to mark the product positioning, which leads to product misleading. It is true that black PCB can show its own technical strength, because black PCB is the most difficult to see the wiring, so both the design and after-sales will suffer unprecedented cost pressure, and the board manufacturers with strong technical strength can not improve the motherboard performance just because of the black color. From the perspective of rational analysis, we also know that color alone is not enough It may improve the performance of the board.
Viewpoint 5. There is no reason, but it has been used all the time.
Source: Hardware 100000 why