Scientists create artificial soft eye with autofocus

Researchers from the Georgia Institute of Technology presented the development of a soft robotic eye that can automatically focus

The created lens is highly sensitive: it can distinguish the smallest details, for example, hairs on the legs of an ant or grains of grain. The discovery brings engineers closer to creating soft robots with advanced vision that do not require separate power supply. It is assumed that such systems can be used in wearable devices and autonomous mechanisms that operate on uneven or dangerous surfaces.

According to the study’s first author, Dr. Corey Zheng of the Department of Biomedical Engineering, traditional robots that use electric actuators are equipped with rigid sensors and electronic components to perceive their environment. However, when creating more flexible and pliable robots that do not rely on electricity, the task of implementing sensory processing and controlling their perception in other ways arises.

Special artificial lens

The lens that the scientists developed is made of a hydrogel with a polymer framework that can retain and release water. Thanks to this, the material is able to quickly change its state – from soft to harder. The hydrogel responds to temperature: when heated, it releases water and shrinks, and when cooled, it absorbs moisture and swells.

The researchers formed a hydrogel ring around a silicon polymer lens and placed the structure in a housing that resembles the human eye. As Corey Zheng notes, the mechanics of the device are similar to the principle of operation of the human visual organ.

How the artificial eye works

Graphene oxide particles, which are dark in color and have the ability to absorb light, were added to the hydrogel. When light of an intensity comparable to sunlight hits them, the particles heat up and transfer heat to the material, causing the hydrogel to contract and pull the lens, providing focusing. When the light source disappears, the material swells again, relaxing the tension.

The development responds to light across the entire visible spectrum. Scientists also noted that this lens can be used as an alternative to traditional glass elements in optical microscopes. Experiments have shown that it is able to distinguish a 4-micrometer gap between a tick’s claws, see 5-micrometer fungal filaments, and identify 9-micrometer hairs on an ant’s legs.

Zheng said the researchers are now integrating the lens into a microfluidic system of valves made from the same sensitive hydrogel. This will allow light to be used not only for imaging but also as a power source for autonomous intelligent camera systems.

Thanks to the adaptability of the hydrogel, the new lens has the potential to expand the range of perception – from simulating the vertical slit pupil of a cat’s eye to reproducing the unusual W-shaped retina of a cuttlefish, which provides perception of a spectrum inaccessible to the human eye.