La couleur verte est donnée avec une avant-dernière couche de protection. C’est une sorte de peinture appelée “solder mask”, qui évite les courts-circuits et l’oxydation.

Elle fut brune à l’origine. La mode est passée et une nouvelle couleur de peinture a été développée.
Il n’y a malheureusement pas de consensus sur la raison du vert.

Une source : https://www.thefreelibrary.com/Soldermask%3A+it’s+not+just+green+anymore+whether+it’s+to+identify…-a0130564604

Have you ever wondered why soldermask is green to begin with? Why didn’t we start out with soldermask that was blue, yellow or red? A number of years ago a there was a discussion about this issue on IPC’s Technet forum. Here are some of the most interesting quotes from that discussion. Which one–if any–is correct? You decide.

“… it goes back to the old military requirements which said that you could have any color soldermask as long as it was green.”

“Soldermask is green because when it was originally produced, the base resin was brownish yellow in color and the hardener was very muddy brown and when you mixed them together you got green. Also, laminates at that time were mostly green so it was easy to accept the idea of green soldermask as well”

“The green color of soldermask was chosen after extensive testing by the US military at the National Materials and Procurement Center in Cedar Bluffs Virginia in 1954 … That particular shade of green produced the right contrast with the white legend ink while being tested under all types of adverse conditions. Every other color at that time failed to produce the same contrast under the same extensive testing”

“Soldermask is green because green has been proven to be the color most visible to the human eye. Individual colors have specific wavelengths, but combinations of wavelengths produce differences in hues and intensities. Yellow and green colors are the easiest to see in normal light. Thus green is the easiest color to see, the color easiest on the eyes and so the color best suited for board inspectors and assemblers”

There you have it: just a few theories about why green soldermask was the only choice for so many years. Do you agree or disagree with these theories? Do you have a different theory? If so I would love to hear from you.

JODY WILLIAMS is the new business development manager at Taiyo America. He is a 20-year industry veteran and has held a variety of technical and management positions for suppliers and fabricators. Williams can be reached at jodyw@taiyo-america.com.