With the ever-evolving needs and advancements in technology, new types of electronics are constantly being developed while some products face obsolescence. However, one component that has remained constant throughout — Printed Circuit Board. Despite the continuous improvements in technology, PCB has stood the test of time and remained an integral part of electronics for over a century. In this article, TechSparks delves into the history of PCB to explore why this technology has not only endured but also become indispensable in the world of electronics.
Birth of PCB
Society Without PCB
Before the PCB was invented, the components inside the electronics were connected in a point-to-point manner, that is to say, the pins of the components needed to be connected to each other through soldering or sockets to form a circuit path. However, this connection method is too complicated and cumbersome, and it can also be implemented for simple applications. Once the internal structure becomes complicated, it will cause a lot of wires to get tangled. In order to find a new and more efficient way to connect circuits, Charles Dukas drew circuit patterns on insulating substrate materials and built wiring conductors through electroplating. This was the early prototype of printed circuits, although at that time it was not yet called a printed circuit board, but rather just a circuit pattern. These early prototypes were not yet used in electronics but paved the way for the development of PCB.
First PCB Board
The first PCB board was born in 1936, when Austrian engineer Paul Eisler demonstrated a radio with a PCB at a technical seminar in the UK. The PCB was made of a paper substrate and copper foil, and the spiral lines on the circuit board were used to connect electronic components. At that time, this innovation was groundbreaking and was quickly adopted by the electronics industry.
Today, printed circuit board is typically made using subtractive manufacturing methods, which involve removing layers of unwanted copper from the substrate to create the desired circuit pattern. Despite this evolution in manufacturing, Eisler’s invention remains the foundation of latest modern PCB technology.
Early Applications of Circuit Boards
When World War II reached its climax, the means of obtaining signals and intelligence became critical for victory on the battlefield. Printed circuit boards played an important role in this area, and the US military utilized PCB in radios.
As electronic products become more and more popular, the U.S. government recognizes business opportunities and expands PCB applications, introducing them into commercial activities such as radio, television, audio and other consumer electronics.
Innovative Developments in PCB Technology
Structure and Materials
At the beginning of PCB development, phenolic resin was used as the base material and copper was used as the conductive material. To increase its commercial value, manufacturers began using a new material for manufacturing called FR-4. This flame-retardant material is made of fiberglass cloth impregnated with epoxy resin and is widely used today due to its excellent thermal stability, high strength, and resistance to moisture, chemicals, and electrical insulation.
The focus of attention has been on how to incorporate more circuits on a single board. In 1961, American circuit scientist Hazeltine Corporation produced the first double-sided PCB using the plated through-hole. This technology breakthrough meant that more circuit patterns could be carried in the same volume.
Once any technology is transferred from the government to the private sector, significant changes can occur, and PCB technology is no exception. As PCB gained popularity in the commercial field, more and more manufacturers began exploring and developing this new electronic technology. This stage marked significant qualitative progress in PCB development, and production processes such as polyimide, double-sided, and flexible all originated from this period.
Printing Technology: This process involves applying the circuit pattern onto the copper foil. The traditional method uses a scraper on a printing machine, but more precise methods such as photolithography technology and tungsten steel scraper are now commonly used.
Copper Plating Technology: This electrochemical process deposits metal copper on the surface of the substrate to manufacture copper foil or a copper plating layer. The traditional process uses electrolytic copper plating and immersion copper, but the equipment and materials used are constantly being improved.
Assembly Technology: Traditional PCBA board is assembled using THT, but this technology is not easily automated. To improve efficiency, SMT with automatic picking robots for artificial plug-ins is used.
In addition to the above three technical means, the development of PCB technology also includes perforation technology, molding technology, and other innovations that have contributed significantly to PCB development.
Expansion of PCB Application Fields
New Energy: The problem of global resource shortage is becoming more and more prominent, and relying on new equipment to solve these problems has become the key. In new energy applications, PCB is used in the control systems of solar panels and wind turbines.
Automotive Electronics: There are more and more electronic components used in modern cars, such as engine control, chassis control, airbags, car audio, etc., which rely on printing technology.
Industrial Control: PCB is extensively used in industrial control applications where precise signal data transmission is essential for high-speed circuit operation.
Future Development Trend of PCB
The peak reached by PCB technology is not accidental but rather due to its ability to follow the trends of the times in its developmental history. TechSparks predicts the following future trends for PCB technology:
High-speed and high-frequency: With the in-depth development of artificial intelligence, 5G, and IoT, PCB is being pushed towards high-frequency and high-speed designs to meet the requirements of these applications. In addition to increasing circuit layout, this trend also requires the development of core components such as IC chip.
Flexible and foldable: Although rigid PCB is still the most commonly used type, the use of flexible and rigid-flex is expanding rapidly, and many emerging devices rely on them. Manufacturers are shifting their focus towards the development of flexible and foldable PCB.
Intelligent manufacturing: Component shortages and supply chain disruptions have been common challenges in the PCB industry. Therefore, future development will shift towards intelligent and automated production processes.
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