A Sensitive And Dynamic Tactile Sensor

These transparent sensors can detect changes in pressure ranging from just the tap of a finger to the equivalent of a full human body weight.

AsianScientist (Apr. 18, 2017) – Researchers from the Ulsan National Institute of Science and Technology (UNIST) have developed a three-dimensional sensor that can detect changes in pressure over four log scales. Their findings, published in Nature Communications, can be used to detect a wide range of pressures ranging from finger touch to the full body weight.

Most existing pressure sensors only work within a narrow range of pressures, limiting their practical applications. Instead, a team led by Professor Park Jang-Ung has developed a new type of pressure sensor that uses foldable substrates and air-dielectric layers.

“Using air as the dielectric layer in graphene field-effect transistors (FETs) can significantly improve transistor performance due to the clean interface between graphene channel and air,” said Park. “The thickness of the air-dielectric layers is determined by the applied pressure. With that technology, it would be possible to detect pressure changes far more effectively.”

Conventional touch panels react to static electricity generated when pressure is applied to the monitor screen. This method can be used to detect the position of the point of contact but cannot provide information about the intensity of the pressure applied. The foldable design relies on changes in the thickness of the layer of air trapped between both sides of the sensor, revealing information about both the position and intensity of the pressure.

In addition, the new sensor consumes less power and has a faster response time.

“This sensor is capable of simultaneously measuring anything from lower pressure (less than 10 kPa), such as gentle tapping, to high pressure (above 2 MPa), such as human body weight,” said study co-author Mr. Ji Sangyoon. “It can be also applied to 3D touchscreen panels or smart running shoes that can analyze life patterns of people by measuring their weight distribution.”

“This study not only solves the limitations of conventional pressure sensors, but also suggests the possibility to apply them to various fields by combining pressure sensor with other electronic devices such as display,” added Park.

The article can be found at: Shin et al. (2017) Integrated Arrays of Air-dielectric Graphene Transistors as Transparent Active-matrix Pressure Sensors for Wide Pressure Ranges.


Source: Ulsan National Institute of Science and Technology.
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