Technology | Highlight
Cuttable Power Transfer Sheet Makes Novel Contactless Charging
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esearchers from the University of Tokyo have developed a new wireless charging system for electronic devices, such as smartphones and smartwatches. The method involves a cuttable, flexible power transfer sheet that charges devices wirelessly and can be molded or even cut with scissors to fit surfaces and objects with different shapes.

Aside from convenience brought about by wireless charging technology, Ryo Takahashi of the Graduate School of Information Science and Technology, believed the usefulness of the technology in emerging fields, like robotics.

Takahashi’s previous study of robotics inspired him to pioneer ways to power devices, such as robots or smartphones, simply and easily. This path led him towards the creation of the first-ever cuttable wireless power transfer sheet. The idea behind this development is for users to be able to reshape the sheet to fit whatever surface upon which they wish to charge devices.

Innovative Design
“You can do more than just cut this sheet into fun or interesting shapes,” continues Takahashi. “The sheet is thin and flexible so you can mold it around curved surfaces, such as bags and clothes. Our idea is anyone could transform various surfaces into wireless charging areas.”

The clever design, which allows these novel features, is also what separates this idea from existing contactless power chargers. Both systems use conductive coils in the charger to induce a current in corresponding coils in the device. However, the cuttable sheet is not only much thinner, but has a wider usable charging area due to the way the coils are designed. These coils are also wired in a way that allowed them to remain intact after the sheet is cut to shape, so they can still charge a device.

“Currently a 400-millimeter square sheet provides about 2 to 5 watts of power, enough for a smartphone. But I think we could get this up to 10 watts, or enough for a small computer,” concludes Takahashi. “In just a few years, I would love to see this sheet embedded in furniture, toys, bags, and clothes.”

The wireless charging sheet can be cut in any possible shape.
Photo 1: The wireless charging sheet can be cut in any possible shape.
The H-tree wiring makes the charger function even after it is cut.
Photo 2: The H-tree wiring makes the charger function even after it is cut.