https://www.eejournal.com/article/a...s-where-did-printed-circuit-boards-come-from/

Development of the radar proximity fuze is a full story unto itself. Development of miniature vacuum tubes that could operate after being shot from a cannon is another full story. Those stories are for other articles. The PCB used in the radar proximity fuze, developed by Centralab, employed a steatite ceramic substrate with screen-printed conductors made from a silver metallic paint.

 

https://www.eejournal.com/article/a...s-where-did-printed-circuit-boards-come-from/

Development of the radar proximity fuze is a full story unto itself. Development of miniature vacuum tubes that could operate after being shot from a cannon is another full story. Those stories are for other articles. The PCB used in the radar proximity fuze, developed by Centralab, employed a steatite ceramic substrate with screen-printed conductors made from a silver metallic paint.

It sounds like an interesting article and I'll finish reading it when I get a chance. But I have to admit that the guy put me off right at the start when he immediately trotted out the claim that IC design tools get all the attention because they sell for big bucks, despite the PCB market (at least per his assertion) being two or three orders of magnitude larger. Without realizing it, he's already undercut his own claim -- if you have a market with 100x or 1000x the customers, you can make much more total profit at much smaller per-unit profit. You also tend to have a lot more players in the market and competition drives the price down. But the two things he overlooks is that IC design tools are simply much more difficult to develop -- and hence have much higher development costs that have to be recovered over a much smaller market -- and IC design tools were an absolute necessity almost from the very start. As he said, he made PCBs in his mom's kitchen (as did a lot of us). Notice that he didn't make ICs in his mom's kitchen. PCB EDA tools lagged because they weren't an absolute necessity for a long time. Again, as he himself experienced, he made professional PCB masks by hand, likely well into the 1980s. This is the way it was done for a long time, and largely because that was how people already knew how to do it, and because for a long time they could be done that way. Like most people, companies resist change as long as the tried and true methods continue to work. But in IC design, the number of devices on a chip -- and the masking steps involved and the design rules that needed to be followed -- almost immediately grew to the point where it was not practical to layout the physical masks by hand. To make matters worse, the cost of a mask error that results in a ruined fab rub is enormous compared to the cost of a similar error that ruins a PCB run.

A couple on metrics that would be interesting to see is the cost of the design tool suite per device fabricated, perhaps both in terms of per-chip/per-board as well as per-component/per-pad. I don't know that the trends of either of those would actually tell us anything meaningful, but it would be interesting to see.

 

This youtube video gives the very interesting story of the development of the proximity fuse, given that ground based anti-aircraft guns were not very effective without it.