Study of tunable lens based on dielectric elastomer actuator
Date Issued
2011
Date
2011
Author(s)
Lin, Zi-Fang
Abstract
With the rapid development of science and technology, all kinds of devices are in the trend of becoming thinner, lighter, smaller, and having lower power consumption.
Current mechanism of commercial tunable lenses utilizes multiple lenses of different focal lengths to form a sophisticated optical system. With the linear motor and gears, the focal length can be tuned by changing the spacing between lenses. However, this mechanism needs a larger System volume. In recent years, many efforts have been taken
to develop tunable lens to reduce the system volume. In this thesis, we present a tunable lens which is driven by dielectric elastomer actuator (DEA). DEA has good mechanical
properties, low cost, low power consumption, and is less affected by temperature and humidity. DEA is formed by a layer of dielectric elastomer sandwiched by two
complaint electrodes. The operating characteristics of DEA are dominated by the applied voltage and the geometric configuration. With increasing applied voltage, which
increases electrostatic force, the complaint electrodes of the actuator gradually become closer to each other and the dielectric elastomer is squeezed. Under boundary restrictions, extruded dielectric elastomer will be buckled. This thesis uses this result on tunable lens system. In the process, the release method is used to fabricate thin and
uniform polydimethylsiloxane (PDMS) membrane and NaCl solution is used as a transparent electrode. In the experiments, we used two common methods to measure the focal length of our tunable lens system. The experimental results show that the focal length can be tuned by 3 mm by applying voltage from 0 V to 900 V. From the current measurement results, the energy is mainly consumed at the moment of DEA deformation. It only needs little energy to maintain the deformation. When the applied voltage is below 600 V, the current is stable. However, the current has irregular impulses when the applied voltage is over 600 V. By observation and speculation, the gold electrode surface has some defects in large deformation. Finally, we setup our
tunable lens on the webcam of a commercial notebook computer to function and capture clear images.
Subjects
Tunable focal length system
dielectric elastomer actuator
electrostatic force
buckling mode
transparent electrode
Type
thesis
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