Summary:

Research out of Georgia Tech demonstrates a new way to read pressure at high speed and resolution.

Pressure sensitive LED pad
photo: Georgia Tech Photo: Gary Meek

How many times have you signed your name on a pad in the grocery store checkout line only to have it barely pick up what you write? New research out of the Georgia Institute of Technology uses a sensor pad to convert pressure directly into light signals, allowing it to capture information at a very high resolution.

The pad could be used to image pressure-reliant information, such as a signature or fingerprint. It could also work as a human-machine interface, acting as artificial skin for robots or as a touch sensitive pad on electronic devices. Researchers at the University of California-Berkeley recently developed a lower-resolution plastic “e-skin” that could be used for similar purposes.

Letters written by applying pressure to the top of the nanowires appear as light at the bottom of the nanowires. Courtesy of Zhong Lin Wang

Letters written by applying pressure to the top of the nanowires appear as light at the bottom of the nanowires. Courtesy of Zhong Lin Wang

“The response time is fast, and you can read a million pixels in a microsecond,” Georgia Tech materials science and engineering professor Zhong Lin Wang said in a release. “This is a new principle for imaging force that uses parallel detection and avoids many of the complications of existing pressure sensors.”

The sensor pad contains thousands of nanowires thinner than human hair that emit light when they are distorted from pressure. The light appears on the opposite side of the pad and can turn on and off within 90 nanoseconds of the application of pressure. The light signal can then be processed and transmitted to another device, such as a computer. The more pressure there is, the more light the nanowires produce. The resulting resolution reaches up to 6,300 dots per square inch.

Researchers think the pad can be further improved by making the nanowires even thinner, which would allow more to be packed into the same area. They are also interested in using a higher temperature fabrication process.

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