In-line Quality-control of UV offset lithographically Printed Electronic-ink by THz technology (IQ-PET)

Printing technologies have been developed to pattern a wide range of electronic materials on diverse substrates, even on flexible paper to realise multifunctional electronic performance. Reliable, fast and low cost, in-line quality control for continuous, high-speed, sheet-to-sheet printing, has been eagerly desired for the large-area electronics industry.

Terahertz (THz) light within the electromagnetic spectrum, is defined to span 0.1 to 10 THz (3.3 cm-1 to 333.6 cm-1) and affords remarkable benefits, being: intrinsically safe, non-ionising and non-destructive. Detecting reflected THz radiation makes it possible to create spectroscopic information and 3D images with its unique coherent sources. Coherence sources present many advantages, such as improving signal-to-noise and ultra-accurate complex amplitude data. THz energy can also probe low energy molecular motion and interactions within molecular lattices, therefore, its spectroscopy and imaging systems have wide scope in applications spanning medical imaging, biological research, pharmaceutical monitoring and semiconductor testing to security, communications, manufacturing and quality control.

In-line Quality-control of UV offset lithographically Printed Electronic-ink by THz technology (IQ-PET) project investigates the changes in THz spectra at each stage of the UV offset printing process for electrically conductive and dielectric inks. This will guide where best to site THz sensors in a commercial offset press to achieve real-time in-line quality-control. The project uses lab-developed, standalone systems (THz quasi-optical reflectometry), and commercial THz TDS (time domain spectroscopy) and antenna Near-field Scanning (NSI) systems to develop a quality control system which can operate with high-speed sheet-to-sheet and roll-to-roll production lines for system level integration in Large-Area Electronics manufacturing.