German engineers have built a camera that is no larger than a grain of salt that may hold the ability to change the future of health imaging and clandestine surveillance. With the help of 3D printing, researchers from the University of Stuttgart created a three-lens camera that is capable of fitting onto an end of the optical fibre; the width of two hairs.

This type of technology could be used as a minimally-intrusive endoscope for exploring the inside of the human body. The camera could also be deployed in virtually invisible security monitors or mini-robots with “autonomous vision” capabilities.

3D printing, also commonly known as additive manufacturing makes three dimensional objects by depositing layer after layer of materials such as plastic, metal or ceramic. Due to the number of limitations during manufacturing, lenses are not able to be made small enough for key uses in the medical field. The team believes the new 3D printing method may represent what they are called a “paradigm shift”.

The tiny eye took only a matter of a few hours to design, manufacture and test. This yielded high optical performances and tremendous compactness according to reports written by the researchers. The compound lens is about 100 micrometres (or 0.1 millimetres or 0.004 inches) wide and a mere 120 micrometres with its casting included.

The lens is able to focus on images from a distance of 3.0 mm and relay them over the length of a 1.7 metre (or 5.6 foot) optical fibre to which it is attached. The “imagining system” is able to fit comfortably inside a standard syringe needle says the team, allowing for delivery into a human organ, or even into the brain. The researchers wrote that endoscopic applications will allow for non-invasive and non-destructive examination of small objects in the medical as well as the industrial sector. The compound lens can also be printed onto image sensors other than strictly optical fibres, such as those that are used in current digital cameras.

The complete study and report have been published within the Nature Photonics journal.