|As a result, the team of bioengineers came up with a relatively cheap and easy method for creating the artificial eyes that may in part mimic natural processes. |
Insect eyes, known as compound eyes, usually consist of hundreds of tiny lens-capped optical units, known as ommatidia. For example, a dragonfly has 30,000 of the structures in each eye.
Individual ommatidia guide light through a lens and cone into a channel, known as a rhabdom, which contains light-sensitive cells. These are connected to optical, nerve cells to produce the image.
The ommatidia are crammed side by side into bulges that create a wide field of view for the insect.
As each unit is orientated in a slightly different direction, the honeycombed eye creates a mosaic image which, although low in resolution, is excellent at detecting movement.
The team created the artificial eye by first creating a tiny, reusable mould with 8,700 indentations.
The pock-marked hemisphere was then filled with an epoxy resin that reacts when exposed to ultraviolet light to create a harder material with different chemical properties.
After being baked at a low temperature to set the material it can be extracted from the mould.
The result is a pin head sized dome with 8,700 raised humps arranged in a honeycomb pattern across its surface.
Each raised hump acts like a lens, focusing any light into the material below.
Over time the concentrated light reacts with the resin to form a cone that guides the light deeper into the structure.
As the light continues to burn a path through the resin it creates a tiny channel, called a wave-guide, which is similar to the rhabdom in an insect's eye.
The reaction of the polymer with the light changes the optical properties of the material meaning that all light that enters the wave-guide is channelled along its length.
The result is a tiny resin dome, covered in lenses and pierced by perfectly aligned wave-guides that channel light through the centre of the dome.
As the channels are created as a direct result of light falling on the lens, the researchers believe they could gain insights into the order in which these structures originally formed in insect's eyes.
"To me it makes more sense to have a lens first," said Professor Lee. "I don't think that you formed the visual nervous system first and then it fanned out."
At the moment, the artificial eye is not connected to any kind of imaging device.
here a very interesting site.
This are my first lenses. I used the tamron 90 and the 2x teleconverter together. I hope you like the result. I had not luck with the light that day and I used a monopod. I hope you like it.