National Physical Laboratory

High-Speed Contactless Electrical Evaluation of Printed Electronics using Inductive Sensors

The market growth of conductive inks for flexible and printed electronics is predicted to increase from $2.3 billion to $3.2 billion by 2025 [1]. It is important that we are able to verify the electrical properties of printed electronics to maintain output quality and reduce wastage. Therefore we are driven to find a suitable non-contact technique suitable to measure the electrical properties of the printed structures during manufacture in a roll-to-roll process.

The emphasis of the work reported here is to use inductive sensors to measure electrical response. The impedance of an inductive sensor is affected by eddy currents induced in nearby conductors such that the electrical loss will be increased. The electrical response will be affected by a number of factors including material resistivity and thickness, temperature and sensor lift-off (distance between sample and sensor).

By controlling temperature and lift-off, we are able to use an inductive sensor to measure electrical impedance and relate it to the electrical properties of printed ink structures. By combining the electrical measuring system with another (such as optical) into a single metrology system for evaluating film properties, with extra thickness and lift-off data, it would be possible to extract the actual electrical resistivity of printed tracks and films.

Further Information

Published: 4 May 2016

Authors: Adam Lewis, Chris Hunt, Owen Thomas and Martin Wickham

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[1] D. Savastano, 'Conductive Inks Drive Growth in Flexible and Printed Electronics', Printed Electronics Now, March 2015

Last Updated: 4 May 2016
Created: 4 May 2016


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