The evolution of the printed circuit board come a long way in the history of electronics. It has developed from the original electrical connection systems developed in 1850s. Early patents for printed circuit boards were issued as early as the 1900s. However, it is not until World War II that people started to use the PCB that we know today.
1920’s to 1940’s- The beginning of the early PCB
In 1925, Charles Ducas of the United States submitted a patent request for a process of creating electrical conduit directly on an insulated surface using an electrically conductive ink. And so the term “printed wiring” or “printed board” was born. In 1943, Austrian scientist, Dr. Paul Eisler, made the first operational printed circuit board that was used as a replacement for huge radio wirings.
Early printed circuit boards were manufactured using of materials like Bakelite, Masonlite, cardboard layers or wooden planks. The materials were drilled to add holes and flat brass wires were bolted onto the board. The component connections were usually made by pressing the end of the brass trace onto the hollow rivet and the component’s leads were only pressed into the open end of the rivets. Sometimes small nuts and bolts are used instead of rivets. The earliest application of the printed circuit boards were used in early tube style radios and gramophones.
1950’s to 1960’s- The evolution of PCB began
During the 1950’s and early 1960’s laminates using different types of resins were introduced. However, all printed circuit boards produced were still single sided. One side of the board contained the circuitry while the other side was the components. Government agencies responsible for new weapons and communications equipment were the biggest influence on the printed circuit board.
Sooner or later, the process replacing the use of brass wires with copper plated to the drilled holes were developed that allowed circuits for both sides to be electrically connected. A 1956 patent issued for a small group of scientists that represented U.S. Army involved the use of base material to which layers of copper foils had been firmly laminated. It used an acid resistant ink printed on the copper foil that was etched to remove the exposed copper. Other methods proposed to deposit ink patterns were stencils, screening, rubber stamping and hand printing.
Double- sided printed circuit boards came together with the introduction of the plating process that allows holes walls to be plated. The 60’s era marked the first use of multi- layer printed circuit boards in the United States. This was the result of the development of the transistor and the miniaturization of other components that created the need for the manufacturers of consumer products to use printed circuit boards.
1970’s to Present- Technological advancements that enhance the PCB
One of the problems of the PCB was the wide spacing of the traces which was considered as more of an aesthetic problem than functional one. During the 1970’s the spacing and the circuitry began to become smaller and the tin/lead coating being used to coat the traces on the board began combining traces together during the soldering process. It the late 1970’s, hot air soldering process was used. It permitted the tin/lead coat to be exposed during etching.
The development of the liquid photo- imaginable masks during the mid- 1990’s had dominated the industry using specialized equipment designed specifically for the application. The invention of the integrated circuit or IC allowed the PCB to reduce in size more. Flexible circuit boards also replaced the stiff boards and cable applications too.
The unending advancements on the electronics technology will keep the production of PCB a dynamic field for so many years. PCB production will continue to be productive as new technologies are discovered everyday to give the world a more sustainable PCB in the future.
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