Truly Flexible Circuits Are A Bit Of A Stretch

a flexible film with a matrix of illuminated color LEDs being stretched

Flexible PCBs have become increasingly common in both commercial devices and DIY projects, but Panasonic’s new stretchable, clear substrate for electrical circuits called Beyolex takes things a step further. The material is superior to existing stretchable films like silicone, TPU, or PDMS due to its high heat tolerance (over 160° C) for the purposes of sintering printable circuit traces.

But, a flexible substrate isn’t very useful for electronics without some conductive traces. Copper and silver inks make for good electrical circuits on stretchable films, and are even solderable, but increase resistance each time they are stretched. Recently, a team out of the University of Coimbra in Portugal has developed a liquid metal ink that can stretch without the resistance issues of existing inks, making it a promising pair with Panasonic’s substrate. There’s also certain environmental benefits of printing circuits in this manner over traditional etching and even milling, as you’re only putting conductive materials where needed.

a flexible film with a strip of LEDs connected by a novel liquid metal ink circuit

After the break, check out Panasonic’s earlier videos showing some of their demo circuits that include a stretchable NFC antenna harvesting electricity even while submerged in water and an LED matrix performing while being, bent, rolled, and stretched. We’re excited to see where this technology leads and when we hackers will be able to create our own stretchable projects.

A great many flexible PCB projects have graced Hackaday, from early experiments to sophisticated flexible PCB projects. Heck, we had a whole Flexible PCB Contest with some awesome flexible projects.

5 thoughts on “Truly Flexible Circuits Are A Bit Of A Stretch

  1. I’ve said it before. About 1974 Elementary Electronics had a crystal radio for the aero band project. And it used flexible circuit board. I can’t remember if it was a regular item from Allied, or you had to order through the magazine

    1. You’re correct. Flexible printed circuits have been around for decades. As a child in the late 70’s I had a Merlin game and the keypad for that was a silver flex circuit (as i later found out). But these circuits are different – these are stretchable. And the unique point of this material is that it is a high temperature stretchable thermoset. I know this because my company made these demo parts for Panasonic. They are deliberately simple demos…

  2. Do copper and silver inks increase resistance every time they’re stretched and retain that higher resistance or does the resistance go back to normal when the length does? If it’s the second that could be useful for strain gauges.

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