IMAGINE if you could see the world through the eyes of an insect, able to spot a bite to eat or a potential predator even when it is almost behind you.
That may soon be possible, using an artificial, ultra-wide angle 鈥渆ye鈥�, about 2.5 millimetres across and developed by researchers at the University of California, Berkeley.
The compound eyes of insects such as bees and dragonflies are made up of tens of thousands of tiny separate lenses, called ommatidia. These all point in different directions to give the insect a wide field of vision. Inspired by these eyes, Luke Lee and colleagues have created a three-dimensional eye based on a polymer resin dome spiked with thousands of light-guiding channels, each topped with its own lens. The eye could be used to give a much wider field of vision to surveillance cameras, cellphone cameras, and surgical endoscopes.
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鈥淭he eye could give a much wider field of vision to cameras and endoscopes鈥�
The artificial eye is made up of 8700 microlenses. To create it, epoxy resin was poured into a hemispherical mould pocked with lens-shaped indentations. The resin was allowed to harden slightly, so the eye could be popped out of its mould.
The team used a resin that acts like a lens when you shine light on it, and hardens completely when exposed to UV light. The eye was heated gently to harden the lens-shaped bumps, while the rest of the resin remained soft.
When a beam of UV light is shone on one of these bumps it focuses the beam, like a lens. The light then burns through the resin like a welder鈥檚 torch into metal and creates a waveguide, or light-conducting channel (Science, vol 312, p 557).
Using a spoke-like pattern of UV light beams to pierce the resin at angles pointing towards the centre of the dome, the team was able to create waveguides that mimic the way an insect鈥檚 ommatidia make light converge on the centre of the eye. 鈥淭hese devices are the first to integrate microlens arrays with self-aligned, self-written waveguides,鈥� Lee says.
The beauty of the technique is that because the microlenses create the waveguides, they are perfectly aligned with them, so that it will be relatively easy to hook the ommatidia up to a photodiode detector. 鈥淚t鈥檚 really lovely work,鈥� says Julian Vincent, director of the Centre for Biomimetic and Natural Technologies at the University of Bath, UK.
The artificial eye will have a 180-degree field of view, far wider than the best available fisheye lens.
