why pcb boards are in green colour？

Printed Circuit Boards (PCBs) are the backbone of modern electronics, connecting and controlling various electronic components within a device. PCBs come in a variety of colors, but the most common color for PCBs is green. The color green has become synonymous with PCBs, to the point that many people assume that all PCBs are green. But why are PCBs in green color? In this article, we will explore the history and reasons behind the green color of PCBs.

History of Green PCBs

The first PCBs were made in the early 20th century and were primarily used in radios. At that time, PCBs were made from materials like Bakelite, a brownish-red resin that was a popular insulating material for electrical components. PCBs were typically brown or black, depending on the color of the Bakelite used.

As technology advanced, new materials like phenolic paper and epoxy resins were introduced, making PCBs more durable and heat-resistant. However, these materials were still brown or black in color.

In the 1960s, the use of fiberglass as a PCB substrate became more common. Fiberglass was an ideal material for PCBs because of its high strength-to-weight ratio and excellent insulation properties. However, fiberglass was white, and the natural color of the material made it difficult to see the copper traces that make up the circuitry of a PCB.

In order to make the copper traces more visible, a soldermask layer was added to the PCB. The soldermask is a layer of polymer resin that is applied over the copper traces to protect them from oxidation and to prevent solder from flowing between the traces during assembly. The soldermask was typically applied in a variety of colors, including blue, red, and black.

However, the color that became most popular was green. The first green PCBs were made by a company called Olivetti in the 1960s. The color green was chosen because it was easy on the eyes and provided a good contrast to the white fiberglass substrate. Additionally, the green color was found to be less fatiguing to the eyes than other colors, making it easier for workers to inspect the PCBs for defects.

Why Green?

So why did green become the dominant color for PCBs? There are several reasons.

Visibility and Contrast

As mentioned earlier, the primary reason for the use of green soldermask was to provide a high contrast between the copper traces and the substrate. The green color makes it easier to see the copper traces, which are essential for the proper functioning of the circuit.

Durability

The green color of PCBs is not just for aesthetics; it also provides durability. The green soldermask is made of epoxy resin, which is a very durable material that can withstand high temperatures, humidity, and other environmental factors that could damage the PCB.

Cost

Another reason for the popularity of green PCBs is cost. Green soldermask is the most commonly produced color, which means that it is often the least expensive option. This is because manufacturers can take advantage of economies of scale, producing large quantities of green soldermask at a lower cost than other colors.

Standardization

Finally, the green color of PCBs has become a standard in the industry. This means that many manufacturers and designers use green PCBs because they are familiar with the color and know what to expect. Green PCBs have become a part of the industry culture, and it is often easier to use the color that everyone else is using.

Conclusion

In conclusion, the reason why PCBs are green is a combination of factors. The green color provides a high contrast between the copper traces and the substrate, is durable, and is often the least expensive option. Additionally, the green color has become a standard in the industry, making it easier for manufacturers and designers to