Flexible circuit boards are becoming more and more common in small and lightweight consumer electronics devices. Manufacturers are seeking novel technologies for flexible circuit manufacturing. Cost-effciency, environmental effects of the manufacturing technology and reducing process steps in manufacturing are the key drivers for development. Printed electronics, especially inkjet technology, has been an emerging viable candidate for flexible circuit board manufacturing over the last few years. Additive processing, minimal material consumption and digitally guided processing are the main attractors of inkjet printing technology. The objective of this thesis work is to demonstrate a flexible circuit board of a commercial mobile phone with inkjet printing technology. The design of the flexible printed circuit board is transferred to inkjet printing technology. The assembly process of the flex module is presented, including laser processing of the substrate, inkjet printing of the circuit layout, component attachment using isotropically conductive adhesive and epoxy and circuit coating. The end result is a flexible circuit, similar to the original design, produced with a new manufacturing technology. The inkjet printed demonstrators were then electrically tested by the original manufacturer of the device. Testing showed that functional prototypes with close to the same performance of the original devices were manufactured. The target of the thesis work was reached. Functional demonstrators with good performance were manufactured with inkjet printing technology. As other outcome knowledge of manufacturing electronics with inkjet printing was further increased, as methods for the design and assembly phase were developed. A specifc image masking algorithm for processing of the inkjet printer bitmap images was introduced in the device design phase. Method for making vias on substrate with inkjet printing technology was demonstrated. Also a method for component attachment on flexible inkjet printed circuits was demonstrated. /Kir11
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