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278 Biomimetics: Biologically Inspired Technologies

Figure 10.6 Different views of the smart pill that is a tube-like biomimetic moving mechanism. (Courtesy of
Hyoukryeol Choi, Sungkyunkwan University, Suwon, Kyunggi-do, Korea.)

biomimetically moving mechanism with inchworm motion for traveling inside the gastrointestinal
track. The flexible skin of the smart pill was fabricated using a 3-D molding technique.
A photographic view of this smart pill is shown in Figure 10.6. Using dielectric EAP, another
application is currently investigated at the Sungkyunkwan University, Korea, is the development of
a Braille display for the visually impaired. It was designed to be compatible with existing Braille
devices and its performance is under evaluation. Blind patients are given display patterns of letters
and symbols and they are asked to recognize them. A photographic view of the display and its mode
of test with a finger placed on the device are shown in Figure 10.7. In Figure 10.8, a photographic
view of a blind person testing the new EAP Braille display is seen. The use of dielectric elastomer
EAP for Braille display has also been a subject of study at SRI (Heydt and Chhokkar, 2003;
Kornbluh et al., 2004) where a simple mechanism was constructed taking advantage of the large
strains and high energy density of this EAP material. For this purpose, individually addressable
diaphragm actuators were developed at the scale of Braille dots of: 1.5 mm diameter and 2.3 mm
center-to-center spacing. The resulting 2-mm-diameter diaphragm actuators that were made of
acrylic films exhibited pressures of up to 25 kPa (3.7 psi) resulting in 10–25 g of actuation force
on the Braille dot that is needed for easy reading. This approach is scalable to large numbers of cells,
and is expected to enable the building of refreshable displays with many lines of characters at an
affordable price.

Figure 10.7 Braille display for visually impaired. (Courtesy of Hyoukryeol Choi, Sungkyunkwan University,
Suwon, Kyunggi-do, Korea.)