Wick et al. [3] demonstrated that active optical elements with variable focal length mirrors selleck chem Imatinib Mesylate can be used to eliminate mechanical motion by motors in zoom lens systems. Changing the surface of the deformable mirror manipulates the optical power of the module.A deformable mirror (DM) is a critical component that can vary focal length by changing the surface deformation. Within an optical system, auto focus and optical zoom can be achieved by using DMs. This has advantages over other refractive type components. Liquid lenses encounter gravity, dispersion, shaking and temperature issues. Liquid crystal lenses suffer from dispersion, temperature, polarizers, and additional AC voltage application issues. A DM has the advantages of small size compared to voice coil motors, freedom from dispersion and resistance to vibration.
Silicon and polymer based MEMS deformable mirrors have been demonstrated [4,5] successfully. However, the high actuation voltage and unidirectional focal length variation limited their applications.Ionic Inhibitors,Modulators,Libraries polymer-metal composite (IPMC) is a promising alternative material for use in fabricating Inhibitors,Modulators,Libraries MEMS-based DMs because of its ability to exhibit large bidirectional actuation with low applied voltage. Figure 1 shows the schematics of the electro-osmotic migration of hydrated counter-ions within the IPMC network. It is a sandwich structure with a layer of Nafion? inside and two layers of metal outside as the electrodes. The chemical formula of Nafion? can be separated into two chains. The hydrophobic main chain forms the backbones to determine the mechanical strength, which is the black bar.
The hydrophilic side chain terminated by ionic groups, such as SO3? for cation exchange, is the red ball noted fixed anion. The working principle of IPMC actuation is that when an electric field is applied, hydrated cations move through the cluster networks which are formed by the chains towards the cathode so that the volume expands near the cathode side and contracts Inhibitors,Modulators,Libraries near the anode side. As a results the IPMC bends toward the anode. According to the actuation mechanism, the real internal stress inside Nafion? should be symmetric and linear distributed along its thickness [6], which is positive in one layer and is negative Inhibitors,Modulators,Libraries in another layer of Nafion?. Traditionally, the IPMC in cantilever beam shape can only generate bending AV-951 motions, but actuators with the capability of complex deformation are highly desirable in many applications.
Pugal et al. [7] presented an electrode patterned IPMC with a twist Regorafenib BAY 73-4506 motion for bionics applications. In recent works [8], we proposed a three-deformational gray box model based on the finite element method (FEM). According to this model, the deformation of IPMC in arbitrary shapes which were confined with different boundaries can be predicted more easily.