PRINTED CIRCUIT BOARDS INSPIRED MANUFACTURING
Peter Woias
University of Freiburg - IMTEK, GERMANY

Abstract
This first segment talks about history and may be left out completely: (When searching for the history of printed circuit board (PCB) technology, one will soon find the Austrian war refugee Paul Eisler as the acknowledged inventor of this concept. He has started first experiments in 1936. During his exile in the United Kingdom a first commercial product (a vacuum tube radio) came out in 1942 using a PCB for carrying and connecting all electronic components. First PCBs produced are on display in the Science Museum, London, however, you may easily miss this unimpressive, small object, although its technology is indispensable in almost every area of our daily living.)

The initial idea behind a printed circuit board, or PCB, is an ordered arrangement, fixation and interconnection of electronic components used for the build-up of an electronic circuit, this done with only few fabrication steps and in a highly automatized process. To achieve this, all materials and fabrication steps involved are used in a truly multifunctional way: The solder will provide electrical connection and mechanical fixation for all parts, the PCB substrate provides mechanical stability and ordered arrangement, and the connecting copper traces serve as electrical conductors, but also, on demand, as heat conductors or sensor elements.

In the meantime, research and development has exploited this idea of "multifunctionality" with PCB-inspired fabrication technologies and PCB-based devices far from "pure" electronics. In addition to electrical traces, optical or fluidic interconnects are realized within PCBs or PCB-like substrates. Active and passive functional elements are part of a PCB, reaching from heat dissipation elements to fluidic actuators or even full microfluidic devices, like micropumps. Finally, PCBs are fabricated as three dimensional devices and may therefore be part of an electronics enclosure or virtually "be" the enclosure for components buried - and protected - within.

The presentation will give a short introduction into today's fabrication technologies used for PCBs and will show practical examples of PCB-based or PCB-inspired micro devices for fluidics, actuation and energy harvesting.