Today’s uber-pocketable gadgets and other microdevices owe largely to the development of printed circuit boards. Its creation has allowed manufacturers to design and move towards increasingly small form factors. But before PCBs were a thing, the world had to rely on a mess of copper wires to connect different components to one another.
The PCBs that everyone knows and uses today would not come until the latter half of the 20th century. However, there were attempts in the early parts of the last century to eliminate the bulky and messy problem of using conventional copper wires. A German by the name of Albert Hanson tried laminating foil conductors to an insulating board – one of the earliest ideas of modern circuit board designs.
There were also patent applications for printed wiring issued in the early 1900s. Thomas Edison even tried his hand at an idea of plating conductors unto linen.
But these attempts are far from the circuit board designs of today. Early inventors tried embedding copper wiring unto wooden planks or cardboard, which doesn’t really make for a compact setup but slightly reduces the wire tangling problems.
Paul Eisler and World War II
An Austrian-born inventor by the name of Dr. Paul Eisler can be credited with the earliest functional designs of today’s printed circuit boards. Because of his Jewish lineage and the prevailing anti-Semitic milieu in the Nazi-controlled German Empire at the time, Eisler was forced to move to England where he got a job in a recording firm. It was in England in 1936 where Paul Eisler first submitted a design containing a functional printed circuit which was used in a radio set. Though he was briefly incarcerated when World War II erupted, he was released and was able to market his idea of a printed circuit to a company.
Near the end of the war, the United States military brass saw potential in Eisler’s printed circuits and integrated them to their anti-aircraft shells.
Postwar Commercial Use and Development
In 1949, an innovation on the production of printed circuit boards came from two scientists affiliated with the United States Army. Stanislaus Danko and Moe Abramson developed the “Auto-Sembly” process. This new innovation replaced the through-hole construction wherein all electronic components had specific wire leads that needed their own holes to be connected to the other side which had the circuit board trace. Each wire had to be manually soldered to the board.
The new auto-sembly process did away with this and the circuit board traces were replaced with interconnected copper foils. The component leads only needed to be dip-soldered. A patent for this was issued in 1956, giving way to more widespread use in consumer products. The widened adoption of printed circuit boards led to further development and innovations concerning its manufacture, design, and efficiency.
The Modern Printed Circuit Board
The 1960’s saw the arrival of the first double-sided PCBs. This was made possible by advanced plating processes that allowed hole walls or what are now termed “vias” to become plated. The circuit design of the boards became increasingly complex. The spaces between tracks began to shrink owing to demand for cheaper production costs.
Innovations in the 1970’s included hot air soldering methods and application of solder masks. Copper circuits is first manufactured and then green solder mask is applied.
The solder mask industry standard today covered everything but the vias and electronic circuitry of the printed circuit boards. Then the pads of the vias are coated with solder. The introduction of integrated circuits in the following years greatly lessened the footprint of the circuit boards, leading to smaller appliances, gadgets, and computers.