ICT 45th Annual Symposium Review

Estimated reading time: 9 minutes

“Yam awlroight, aer kid?” A friendly greeting in the local dialect as the Institute of Circuit Technology (ICT) held its 45^th annual symposium June 4, 2019 in Dudley at the Black Country Museum—a symbol of the spirit of innovation in engineering technology and the entrepreneurial and manufacturing skills that had established that region’s supremacy in leading the original Industrial Revolution.

ICT Technical Director Bill Wilkie opened the proceedings with a good-humoured welcome address in which he likened delegates to kernels of knowledge and the ICT to a metaphorical watering can that encouraged their knowledge to germinate, flourish, blossom, and propagate.

He was delighted to introduce keynote speaker Ashutosh Tomar, technical manager (research) with Jaguar Land Rover—the U.K.'s largest automobile manufacturer. Tomar’s speciality was the development of smart surfaces, structural and flexible electronics. His presentation entitled "Applications of Flexible and Hybrid Electronics in the Car" gave delegates the opportunity for a privileged look at some of the advanced electrical and electronic features hidden beneath the bodywork and interior trim of Jaguar Land Rover vehicles.

"Today’s automotive industry is as high-tech as aerospace. The electrical architecture is growing exponentially," said Tomar. He continued, "In our premium vehicles today, we have at least 175 features—probably double that if we include connected-car features and infotainment. The rate is continuing to increase with advances in self-learning, electric, and autonomous vehicles, which directly impact what goes underneath the body. And we have an ever-growing number of electronic control units in the car together with a rapidly increasing volume of sensors and smart sensors and their associated input-outputs and actuators inside of the car. There’s no room to put any more electronics!"

To illustrate some realities, Tomar’s graphics showed the locations of over 100 sensors, the enormity of a traditional wiring harness—eight kilometres of wire weighing 90 kilograms—and the complex labour-intensiveness of its construction. Tomar saw flexible circuits as the future of electrical distribution systems, and structural electronics as enablers for lightweight electronics features—such as displays, interior lighting, haptic sensing, and gesture recognition systems—building them into visible hard and soft surfaces within the car interior. He passed around an example of an integrated overhead lighting and control panel made by injection-moulded structural electronics technology, which offered a thickness reduction from 50 mm to 3.5 mm—a 60% weight saving and a 70% reduction in physical bill of materials.

Tomar went on to discuss possibilities in self-sustained wireless sensors—containing sensing, energy harvesting, battery technology, and transmission all in one package—and adapting flexible circuit and printed electronics capabilities to integrate electronic control units and electrical distribution systems. The effect would be to dramatically reduce mass and volume to eliminate large numbers of connections and achieve logistic benefits and a high level of automation in manufacture.

Although there remained some technical challenges to overcome and many thousands of hours of reliability testing to complete, it was only a matter of time before the full benefits of these concepts would be realised. It was clear that form was becoming at least as important of a consideration as a function: “What we can do is only limited by our imagination and vision!” Tomar’s keynote certainly captured the imagination of his audience and provided the basis of a very lively question-and-answer session.

The closely related topic of printed electronics technology was the subject of the presentation by Jack McGhee who had recently completed a post-graduate study of new materials and methods at Loughborough University. Loughborough has a long history of formulation and characterisation of materials for printed electronics. McGhee explained that although the printing of conductive materials enabled inexpensive mass production of electronic devices that could be thin and flexible, those devices would typically have lower performance than conventional electronics. Whereas silver and carbon inks had most commonly been used, his research had examined the effects of integrating ceramic conducting and semiconducting materials into inks to improve their properties and increase their functionality. He discussed the incorporation of metal oxides, such as gallium-zinc oxide and indium-tin oxide, and more complex oxides, such as ferrites.

As printed, these materials gave some advantages over straightforward silver and carbon, but to achieve optimal conductivity, the materials required sintering and fusing. Of the several post-processing techniques investigated, some interesting results had been achieved with laser scanning, which could give effective local temperatures between 800°C and 1,300°C and decrease resistivities from typically 50 ohms per square to 3 ohms per square. Whereas originally it had been believed that simple fusing was the primary effect, McGhee demonstrated how the nanostructure of the materials could be manipulated by altering parameters and explored possible mechanisms. With indium-tin oxide, there was evidence that crystal growth occurred during re-oxidation, such that it formed microscopic wires and branched structures. And that the final structure depended on laser power and the optical properties of the material. He showed several examples.

Applications for laser-treated printed metal oxides included frequency selected surfaces, high-surface-area coatings for sensors, printed films for solar cells, tuneable capacitors, printed humidity sensors, and printed temperature sensors. There were also potential applications in 3D printed sensors. Ongoing printed electronics projects at Loughborough included screen-printed textile supercapacitors, printable active devices, and power dissipation through printed materials.

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