Back in July, I wrote about a team of researchers collaborating between Northwestern University and the University of Illinois to create a camera similar to that of a fly’s. With a spherical surface shape, hundreds of small cameras point in different directions to obtain a wide-angle view of the world.
One issue with this design, however, is the inability to focus. Traditional cameras use a series of lenses that move slightly in concert to create depth perception. That is, making a distant object clearer will necessarily make objects closer to the camera fuzzier. In contrast, flies and other animals with similar eyes see everything equally sharp at all times.
For many applications, this isn’t really all that big of an issue. But for others, it’s a huge one. For example, if doctors want to insert a tiny camera to get a read on where damaged tissue resides so that they can cut it out, it’s important to know what pieces are closer than others. To try to tackle a spherical, multi-lens, bug-like camera that can also focus, Ohio State University researchers turned to fluids.
Their camera is similar to the one I wrote earlier, but with some pretty major advantages. First, it’s much smaller – like pretty tiny – and it has a lot less individual lenses attached (more like 9 instead of 180). Secondly – and most importantly – it’s actually a composition of several separate dome-shaped pockets of fluid. And by changing the amount of fluid in the different pockets, the researchers can change the shape of the overall camera.
That’s how it gives depth perception. Sort of like a human eye, which has muscles that change the shape of the lens to focus on different objects.
The camera was recently described in the Technical Digest of the 25th IEEE Internatioal Conference on Micro Electro Mechanical Systems. In their described tests, researchers switched its focus among microscopic objects arranged at different distances. They printed each of the letters in O-H-I-O on top of tiny platforms of different heights, and pointed the lens at them from above. The lens was able to focus on each letter in turn, while the others became more or less blurry depending on how far away they were.
Of course, there are some pretty major obstacles still to be overcome. For one, the fluids that are at the root of the shape-changing lens currently come from an external source that has to be pumped manually. To make the design more appropriate for use in electronics, the engineers created an otherwise identical shape-changing lens from an electrically active polymer, which expands and contracts based on electrical signals. That lens has undergone initial testing, and the engineers have submitted a paper on it to an academic journal.
With patents pending, the researchers hope this design could eventually be used in many applications, including the aforementioned medical testing and surgery as well as in smartphones, which can’t currently actually zoom or focus.
The researchers on the project include Yi Zhao, associate professor of biomedical engineering and ophthalmology, and doctoral student Kang Wei.