Lens array could make skin-cancer scans more efficient

A new microscope could provide doctors with a handheld device for looking for signs of skin cancer.

Researchers in Germany have developed technology to take high-resolution images of the skin that are captured so quickly that the microscope can be held in the hand without blurring the pictures.

Existing equipment used to examine whether skin blemishes are malignant is either bulky or can only take one image of a small area at a time, so has to slowly scan the skin in order to capture multiple images that can then be combined.

The new technology, developed at the Fraunhofer Institute for Applied Optics and Precision Engineering IOF in Jena, uses an array of tiny lenses that work simultaneously to create a larger image assembled by a computer.

The Fraunhofer researchers have initially produced a 42mm by 36mm demonstrator device with 9,000 lens channels. It is lightweight and flat enough to be handheld but the technology could potentially be replicated for a unit of any size.

‘The really big advantage is that you can adjust the size of the array to the area needed,’ IOF group manager Dr Frank Wippermann told The Engineer.

‘The other advantage is that we use a replication process for generating the lenses, so you create a master structure only once — it’s like stamping — and that gives you the key to production costs.’

This Fraunhofer-developed process involves pressing a master die onto a glass substrate coated in liquid polymer and shining UV light on it, so that the exposed polymer hardens to create the lenses.

The lens array is created from three stacked glass plates with lenses above and below them, and an additional two achromatic lenses in each channel, so that the light passes through a total of eight lenses.

The technology is part of a wider Fraunhofer project developing tiny multi-aperture imaging optics for cameras and microscopes.