Human-like lenses for cell phone cameras
Lenses in optical instruments are currently rather standard fare for manufacturers. They are hard materials made to see things of certain sizes at specific ranges of distance. The lens of the human eye, however, is deformable and made of tissues that can change shape in a process called accommodation to focus on virtually anything over large distances. Contraction and relaxation of small muscles attached to the lens change the curvature and thicken or flatten the lens as needed. The ability to mimic nature's capabilities by manufacturing flexible, tuneable lenses has exciting potential for a number of applications in biomedicine and consumer electronics. Such technology is directly applicable to intraocular lens (IOL) implants and would enable enhancements in performance for such devices as mobile phone cameras and flexible liquid crystal displays (LCDs). Scientists are developing such technology with EU funding of the 'Parylene based artificial smart lenses fabricated using a novel solid-on-liquid deposition process' (Parylens) project. A previous Framework Programme project (Multipol) demonstrated the use of a polymer thin film (Parylene) deposited on liquid surfaces for hermetically sealing the liquid without deforming it. Subsequently applied external forces, either with the body's eye muscles or with transparent conductive electrodes (electrically activated polymers (EAPs)), can deform the lens changing the focal length. One of the key scientific objectives of the Parylens project was creation of the appropriate degree of freedom to enable accommodation. In addition, scientists had to maintain the many favourable properties of Parylene, including biocompatibility, transparency and chemical non-reactivity (inertness). To date, the flexibility issue has been addressed and nanoparticles, known for their anti-bacterial properties, have been deposited on the surface. In addition, scientists have exploited a process (the so-called sol-gel process) that produces a wet, solid-like material to make the liquid body of the lens compressible. Finally, a first prototype of a flexible LCD has been produced. Parylens is going beyond the state of the art in solid-on-liquid encapsulation, paving the way for the next generation of optical devices and a tremendous boost in the competitiveness of the EU economy.
