A less expensive method of creating smart woven and fabric displays – in a variety of sizes

Researchers have developed a next-generation smart textile – one that combines LEDs, sensors, energy harvesting and storage – that can be produced cheaply, in any shape or size, using the same machines used to make the clothes we wear every day.

An international team, led by the University of Cambridge, had previously demonstrated that wicker displays could be made in large sizes, but earlier examples were made using special manual laboratory equipment. Other smart textiles can be produced in dedicated microelectronics fabrication facilities, but these are very expensive and generate large amounts of waste.

However, the team found that flexible displays and smart fabrics can be made much cheaper, and more sustainably, by weaving electronic, optoelectronic, sensing and energy fiber components on the same industrial looms used to make conventional textiles. The results are reported in the journal Science Advancesdemonstrating how smart textiles can become an alternative to larger electronics in sectors including automotive, electronics, fashion and construction.

Despite recent advances in the development of smart textiles, function, dimensions and form have been limited by today’s manufacturing processes.

“We can make these textiles in specialized microelectronics facilities, but this requires an investment of billions of pounds,” said Dr Sanghyo Lee of Cambridge’s Department of Engineering, first author of the paper. “Also, manufacturing smart textiles this way is very limited, as everything has to be made on the same rigid wafers used to make integrated circuits, so the maximum size we can get is about 30 centimeters in diameter.”

“Smart textiles are also limited by a lack of practicality,” said Dr Luigi Occhipinti, also from the Department of Engineering, who co-led the research. “You think about the kinds of bending, stretching and folding that normal fabrics have to withstand, and it’s a challenge to incorporate that same resistance into smart textiles.”

Last year, the same researchers demonstrated that if the fibers used in smart textiles are coated with a material that can withstand stretching, they can be compatible with conventional weaving processes. Using this technique, they produced a 46-inch woven demonstration screen.

Now, researchers have shown that smart textiles can be made using automated processes, with no limitations on size or shape. Various types of fiber devices, including energy storage devices, light-emitting diodes, and transistors are fabricated, encapsulated, and blended with conventional fibers, both synthetic and natural, to make smart textiles by automated weaving. The fiber devices are interconnected by an automatic laser welding method with an electrically conductive adhesive.

All processes are optimized to minimize damage to electronic components, which in turn makes smart textiles durable enough to withstand the stretching of industrial looms. The encapsulation method was developed to take into account the functionality of the fiber device, and the mechanical forces and thermal energy were systematically investigated to achieve automatic weaving interconnection and laser-based interconnection.

The research team, working in partnership with textile manufacturers, was able to produce smart textile test patches approximately 50×50 centimeters in size, although these can be scaled up to larger dimensions and produced in large volumes.

“These companies have well-established manufacturing lines with high-throughput fiber extruders and large looms that can weave one square meter of textile automatically,” said Lee. “So when we introduce smart fibers into the process, the result is essentially an electronic system that is manufactured in exactly the same way as any other textile.”

Researchers say the large, flexible screens and monitors could be made on industrial looms, rather than in dedicated electronics manufacturing facilities, which would make them much cheaper to manufacture. Further optimization of the process is required, however.

“The versatility of this textile is truly extraordinary,” says Occhipinti. “Not only in terms of its mechanical flexibility, but the flexibility of the approach, and to use a sustainable and environmentally friendly electronics manufacturing platform that contributes to reducing carbon emissions and enabling real applications of smart textiles in buildings, car interiors and clothing. . Our approach is quite unique in that way.”

This research was supported in part by the European Union and UK Research and Innovation.