Printed circuit boards began as electrical connection systems, first developed during the 1850s. Initially, rods or strips made of metal connected large electric components on wooden bases. Eventually, wires connected to screw terminals replaced the metal strips, and metal chasses replaced the wooden bases. Then, due to increased operating needs for products using these boards, the design size diminished.
Evolving Printed Circuit Board Assemblies
In 1925, a US patent was submitted, consisting of an electrical path on an insulated surface. For this, conductive inks and a stencil were used, thus leading to the name, “printed circuits.” Eighteen years later, another man patented an etching process for making circuits or a conductive pattern on top of a layer of copper foil-bonded glass fiber as the non-conductive base.
Although a popular technique, it was not until the 1950s, when the transistor was introduced specifically for commercial purposes, that the copper-backed process was widely accepted. After the transistor’s advent, components became extremely small, forcing manufactures to use printed circuit board assemblies as a means of reducing the overall size of the electronic component.
By 1961, Hazeltyne, a US firm, patented hole technology and its use in multi-layer printed circuit board assemblies. The result was that component density increased, and the newly close-spaced electrical paths changed the design of printed circuit board assemblies dramatically. During the 1970s, experts introduced integrated circuit chips, which were quickly added to the design and manufacturing process.
The Future of Printed Circuit Board Assemblies
Today, printed board circuit assemblies are sophisticated and used by multiple industries for various applications. For example, these boards play an intricate role in personal and business computers, as well as computers used in airplanes, automobiles, boats, and more. Virtually any type of computer system has one or more printed circuit board assembly.
For printed circuit board assemblies made and used today, there is no such thing as “standard.” The boards currently designed and manufactured have very specific functions, and companies that make them thereforerequire tremendous expertise.
The decreasing size of electronic components is what drives the manufacturing of printed circuit board assemblies. These boards are becoming smaller, but also more densely packed, while still providing increased electronic capabilities.