Automated device tests printed electronics as they are made

Engineers in Finland have developed equipment for automatically testing printed electronics as they are produced.

The device draws inspiration from similar equipment used when making large printed circuit boards, testing and measuring different components on a roll of printed electronics without the need to manually connect to each one.

A team from VTT Technical Research Centre commissioned the equipment from local company Probot Oy for the pilot production environment run by VTT and printed electronics community PrintoCent in the town of Oulu.

Printed electronics offers a way of producing electronic components and circuits by printing them directly onto a substrate, enabling rapid and low-cost mass production of thousands of components in a single roll of material.

‘If you have a roll of, say, OPBs [on-chip peripheral buses], the customer wants to know what is the efficiency of each of them; what is the yield within the roll,’ said VTT team leader Mikko Paakkolanvaara, adding that collecting this information manually would be ‘awfully time consuming and expensive’.

The equipment uses a series of spikes that can be configured for the specific printing layout being produced. It can run either at the end of the manufacturing process or in between different printing layers to monitor progress.

When these spikes come into contact with the components on a section of the roll of printed electronics, they can test whether each one is working and measure its resistance, capacitance and conductivity and record this information in a database.

In the case of visual display components such as printed organic light-emitting diodes (LEDs), the spikes supply current to the display and a camera takes an image to record whether it is emitting light. Paakkolanvaara said the system could even be configured to identify individual pixels in a display that wasn’t working.

He added that although the equipment had been produced for VTT’s pilot production environment, it could be adapted for commercial use with few changes.