History of Circuit Boards Through the 20th Century

History of Circuit Boards

The Beginning of the Twentieth Century

The History of Circuit Boards dates back to the beginning of the twentieth century. Albert Hanson, a German scientist, and inventor, first described the use of multiple layers of foil conductors laminated to an insulating board in 1903.

In 1927, Charles Ducas’s circuit method placed an electronic path directly onto an insulated surface. The wires were printed onto the board through a stencil, and the ink applied could conduct electricity. This process is an early version of electroplating.

Next came Paul Eisler. He invented the first printed circuit. This was in England in 1936 while working on a radio set. Eisler’s early PCBs were first used in small radio sets. They were intended to be used by the British and American military during World War II. However, the US military ended up incorporating PCBs into anti-aircraft shells. In 1947, the First double sided PCB’s with through-hole plating began production.

The Middle of the Twentieth Century

In the middle of the Twentieth century, the types of materials used for the board was shifting to different resins and other materials. However, there was a problem with these materials. Only one side could have the printing. Therefore, the wiring would be on one side, while the electrical components would be on the other.

In 1956, the U.S. Patent Office granted a patent to a small group of scientists representing the U.S. Army. The patent was for the “Process of Assembling Electrical Circuits”. The process involved drawing the wiring pattern and then photographing it onto a zinc plate. This plate was the first step in creating a printing plate for an offset printing press. By using this plate they could print the wire in acid resistant ink on the copper foil. Furthermore, the use of an acid solution would etch the copper foil. This was a giant leap forward. Therefore, in 1960, a multilayer PCB design began production.

The End of the Twentieth Century

In the 1970s, the circuitry and overall size of the boards got a lot smaller. Also, there was an increase in the use of hot air soldering methods. During the 1980s, Surface mount parts became the preferred option. This was over through-hole components. This led to further size reductions. All while maintaining the same level of functionality.

In the 1990s, the complexity of modern circuit boards continued to go up. However, the size of the boards and costs of materials continued to go down. Once developers were able to start using multi-layer circuit boards they were able to minimize the size. Also, they were able to incorporate combinations of rigid and flexible PCBs in a range of devices. 1995 was the beginning of the use of micro-via technology in PCB production. Which ushered in the era of HDI (High-Density Interconnect) PCB’s.