Dr Steve Lee with his droplet lens invention. Photo by Stuart Hay.

Dr Steve Lee with his droplet lens invention. Photo by Stuart Hay.

A drop of optics

Optical microscopes are a valuable tool for any scientist. The basic way to make microscope lenses has been around since the 16th century.

Now, by harnessing the natural shape of water droplets, ANU researcher DR STEVE LEE is has invented a new way to make microscope lenses that is compatible with the humble smart phone - transforming the field of microscopy. DR PHIL DOOLEY, BSc (Hons) '90, PhD '99 reports.

Like many great discoveries, the first droplet lenses were made by accident.

Dr Steve Lee was working on moulded lenses for endoscopes at the time.

He accidentally left a batch of clear polymer polydimethylsiloxane (PDMS) droplets in the oven overnight.

"I nearly threw them away," he says.

"I happened to mention them to my colleague Dr Tri Phan, who is a doctor at the Garvan Institute, and he got very excited."

Lee, from the Research School of Engineering, is now using the same method to make his lentil-sized microscope lenses from droplets of the clear polymer commonly used for contact lenses.

The elegant beauty of the droplet forms the perfect lens curvature.

"We make it by putting droplets of polymer onto a microscope cover slip and then inverting it.

"Then we simply let gravity do the work, pulling it into the perfect curvature," he explains.

The result of fine tuning the shape of the droplet is a lens that magnifies 160 times with a resolution of about four microns - comparable with a medium powered pathology microscope.