OSAKA – Sumitomo Electric has developed a flexible printed circuit with circuit layers connected by conductive paste. It is based on the firm’s metal nanoparticle technology.

The newly developed FPC is expected to improve the wiring design flexibility of mobile terminals and other electronic devices, and to save space.

The method for connecting circuits with conductive paste (called paste via method) consists of forming a circuit, drilling holes in the insulating film, and filling the holes with conductive paste. Since the paste via method does not use copper plating, it reportedly reduces the thickness of circuit boards by nearly 30% compared with that of traditional boards, the firm says.

In April, the firm started full-scale operation of its mass-production line at Minakuchi Works, and has recently started to ship the double-sided FPCs.

Sumitomo Electric will promote the overseas expansion of FPC mass production systems and the expansion of FPC sales for use in liquid crystal panels and touch-sensitive panels of mobile terminals.