Why are PCB usually green? 为什么PCB我们一般使用绿色

The green that you see is the color of the solder mask that is laid on the topmost layer of the assembly (to prevent short circuits, soldering errors, etc).  There doesn't seem to be a clear consensus as to why most solder mask is green.  However, here are some of the theories: Green was the color of the original resins that were melted to create solder mask in the early days of PCB manufacturing. Green came from some military standard, or military testing that indicated...Green is the best background color for contrast against white silk-screened text on the surface of the PCB in different environmental conditions. One is no longer limited to green however, and most PCB manufacturers like to advertise the fact that they can produce boards with all different colored solder masks.

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We have another opinion. The green color came from the military- at the time.  There are other colors available.  In the military(USN), it was not just the solder masks, but conformal coatings that changed the colors.  In one job, the company's marketing colors were blue, so I paid extra for the precise shade of blue for my PCBs.The color of FR4 (fibreglas) material, commonly used in PCB manufacturing is a weird shade of grey/brown.  If it had no solder mask or coating, the end result would be kind of a dull grey/khaki/brown one used to see in certain old TV sets, where the PCB was integrated into the steel vacuum tube mounting frame.  These boards did have legends for the components screened onto them, but they were not coated in any fashion.Conformal coatings came about in the military to provide some protection from moisture and corrosion.  Since the military was almost the largest customer, it was easier and cheaper for many companies to provide coatings and silk screenings to all customers.  After all, you still had to pay the NRE and material costs of these screenings and coatings, but it was greatly reduced prices than the original prices.

 

Depends for which PCB color you are talking about. If the PCB itself is green, that indicates, that its made from glass-epoxy which is naturally green. Also your PCB could be made in every single color that exist. The finishing color is usually a solder mask. This mask is applied for safety reasons, for preventing eventual short circuits and etc. It could be every color, depends on the client's specifications.

 

The original masks used a base resin that was a "brownish yellow" and a hardener that was a deeper muddy brown. When they were mixed together they created a honey brown color that apparently not very appetizing. They tried adding red pigments but it became a rusty adobe color and using blue simply made it a darker brown. None of them were very appealing colors. Since the laminate materials at the time had a green hue they tried adding more yellow and some blue and ended up with an acceptable green color. It became the standard color we are still using today.

 

你看到的是阻焊层是绿色的,它是放在最上层的组件的颜色(为防止短路,焊接错误等)。似乎没有一个明确的共识,为什么大多数焊料面膜是绿色的。然而,这里有一些理论:绿色是在印刷电路板制造的早期的树脂,在印刷电路板的颜色中,绿色是在不同的环境条件下,在印刷电路板的表面上,绿色是最好的背景颜色,一个是最好的背景颜色,一个是不限于绿色,但大多数印刷电路板制造商喜欢做广告的事实,他们可以生产板的所有不同颜色的焊接口罩。

 

我们有另一个观点。绿色的颜色来自于军队--当时。还有其他颜色可供选择。在军事(美国海军),这不仅仅是焊接面罩,但保形涂层改变颜色。一份工作,公司的营销的颜色是蓝色的,所以我支付额外的为我的PCBs蓝色深浅。FR4的颜色(fibreglas)材料,常用于PCB的制造是一个奇怪的灰色/褐色。如果它没有阻焊膜或涂层,最终的结果将是一个暗灰色/卡其色/棕色用来看到某些旧电视机,在PCB集成到钢真空管安装架。这些木板确实有传说中的组件进行筛选,但他们没有在任何时尚的涂层,保形涂层来提供一些保护免受潮湿和腐蚀。由于军队几乎是最大的客户,这是更容易和更便宜的许多公司提供涂料和丝绸之路的所有客户。毕竟,你还不得不支付NRE和这些场次和涂层材料的成本,但却大大降低了价格比原来的价格。

 

取决于你所谈论的印刷电路板的颜色。如果印刷电路板本身是绿色的,那说明,它的玻璃环氧树脂,这是自然的绿色。而且你的印刷电路板可以在每一个单一的颜色存在。整理的颜色通常是一个焊料掩模。该掩模适用于安全的原因,以防止最终的短路等,这可能是每一个颜色,取决于客户的规格。

 

原始面具用基础树脂,是一种棕黄色和硬化剂,是一种深褐色的。当他们混在一起,他们创造了一种蜜褐色,显然不是很开胃。他们尝试添加红色颜料,但它变成了一个生锈的颜色和使用蓝色简单地使它成为一个深棕色。他们中没有一个是非常有吸引力的颜色。由于在当时的层压材料有一个绿色的色调,他们尝试添加更多的黄色和一些蓝色和结束了一个可以接受的绿色。它成了我们今天仍在使用的标准颜色。