[info] kurzweill: physorg: tactile actuator polymer

Tue Jun 10 11:53:32 UTC 2008

(
http://physorg.com/news131968663.html
)

Researchers Design Band-Aid-Size Tactile Display
By Lisa Zyga
Researchers from Sungkyunkwan University in Korea and the University of
Nevada in the US have developed a flexible tactile display that can wrap
around the finger like a band-aid. The device could be used as a Braille
display among other applications ...
Researchers from Sungkyunkwan University in Korea and the University of
Nevada in the US have developed a flexible tactile display that can wrap
around the finger like a band-aid. The device could be used as a Braille
display, among other applications. Credit: Ig Mo Koo, et al.

Currently, we get most of our information from computers through visual
and audio features. But as researchers from Korea point out, the most
widespread sense on the human body is touch. While some tactile computer
devices do exist, the researchers are trying to take full advantage of
this overlooked sense with the development of a tactile display that can
be wrapped around your finger like a band-aid.

In an upcoming issue of IEEE Transactions on Robotics, Ig Mo Koo, Hyouk
Ryeol Choi, and co-authors from Sungkyunkwan University and the
University of Nevada explain how they have designed the innovative
tactile display based on soft actuator technology. Overcoming the
rigidity and bulkiness of current devices, the new display is soft and
flexible enough to be wrapped around almost any part of the human body,
such as the fingertip, palm, or arm.

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“The big advantage of a wearable tactile display compared to a normal
tactile display is flexibility,” Koo told PhysOrg.com. “When you apply a
normal device to a non-flat surface like human skin, it is impossible to
stimulate the whole skin through its shape. In the case of a wearable
tactile display, however, it can be applicable to many kinds of surfaces
without the limitation of stimulus area because of its flexibility.”

The researchers hope that the soft display might provide a means of
communication for the visually impaired (for example, as a Braille
display). It could also have applications as a tactile display cloth,
virtual reality keyboard, tele-surgical glove, tele-feeling transferring
system, and more.

“Let’s assume someone needs a glove-type wearable tactile display,” Koo
said. “When we make it using a normal device, stimulus elements can be
attached only in a limited area. But if we develop it as a wearable
tactile display, it is possible to not only make a glove-type in the
process of manufacturing, but also apply stimulus elements on the whole
part of the glove.”

The key material to the display is an electroactive polymer that can
stimulate the skin without using any additional electromechanical
transmission. The polymer consists of eight layers of dielectric
elastomer actuator films which have been sprayed with electrodes in a
specific pattern.

Along with a protective layer to separate the electrodes from the skin,
the entire polymer sheet is about 210 micrometers thick. In their study,
the researchers fabricated an 11 x 14 mm sheet with Velcro on the edges,
and rolled it up in the shape of a thimble to be worn on the finger.

The display can convey information to the wearer when the electrodes
induce a voltage across the films. A voltage causes the films to
compress down and expand outward. In doing so, the films put pressure on
the wearer’s skin, inducing a “mild sensation.” Like most polymers, the
device is hyperelastic, meaning that it can experience large amounts of
elastic strain and recover its original shape.

This simple stimulation mechanism, which doesn’t require complex
electronics, is one of the greatest advantages of the soft tactile
display compared with current displays. Its other benefits include
efficient power usage, cost-effectiveness, and easy fabrication. As the
researchers note, the new display has lower power and displacement
values than is considered optimal, which may limit its applications to
specific areas.

Koo added that, in the future, the team plans to improve display
performance, as well as develop applications such as a tele-feeling
transferring system and glove-type tactile display device.

More information: Koo, Ig Mo; Jung, Kwangmok; Koo, Ja Choon; Nam,
Jae-do: Lee, Young Kwan; and Choi, Hyouk Ryeol. “Development of
Soft-Actuator-Based Wearable Tactile Display.” IEEE Transactions on
Robotics. To be published.