Biomimetic artificial vision device brings colour to perception

This is the claim of Georgia State University researchers whose new type of artificial vision device incorporates a novel vertical stacking architecture that allows for greater depth of colour recognition and scalability on a micro-level. The new research is published in ACS Nano.

“This work is the first step toward our final destination­–to develop a micro-scale camera for microrobots,” said assistant professor of physics Sidong Lei, who led the research. “We illustrate the fundamental principle and feasibility to construct this new type of image sensor with emphasis on miniaturisation.”

Lei’s team was able to lay the groundwork for the biomimetic artificial vision device, which uses synthetic methods to mimic biochemical processes, using na­notechnology.

“It is well-known that more than 80 per cent of the information is captured by vision in research, industry, medication, and our daily life,” he said in a statement. “The ultimate purpose of our research is to develop a micro-scale camera for microrobots that can enter narrow spaces that are intangible by current means, and open up new horizons in medical diagnosis, environmental study, manufacturing, archaeology, and more.”

This biomimetic ‘electric eye’ is said to mark an advance in colour recognition, which is missed in current research due to the difficulty in downscaling the prevailing colour sensing devices. According to the team, conventional colour sensors typically adopt a lateral colour sensing channel layout and consume a large amount of physical space and offer less accurate colour detection.

Researchers developed the unique stacking technique which offers a novel approach to the hardware design. Lei said the van der Waals semiconductor-empowered vertical colour sensing structure offers precise colour recognition capability which can simplify the design of the optical lens system for the downscaling of the artificial vision systems.

Ningxin Li, a graduate student in Dr. Lei’s Functional Materials Studio who was part of the research team, said recent advances in technology make the new design possible.

“The new functionality achieved in our image sensor architecture all depends on the rapid progress of van der Waals semiconductors during recent years,” said Li. “Compared with conventional semiconductors, such as silicon, we can precisely control the van der Waals material band structure, thickness, and other critical parameters to sense the red, green, and blue colours.”

The van der Waals semiconductors empowered vertical colour sensor (vdW-Ss) represent a newly-emerged class of materials, in which individual atomic layers are bonded by weak van der Waals forces.

“The ultra-thinness, mechanical flexibility, and chemical stability of these new semiconductor materials allow us to stack them in arbitrary orders. So, we are actually introducing a three-dimensional integration strategy in contrast to the current planar micro-electronics layout. The higher integration density is the main reason why our device architecture can accelerate the downscaling of cameras,” Li said.

Lei said his team will continue pushing these advanced technologies forward using what they’ve learned from this discovery.

“This is a great step forward, but we are still facing scientific and technical challenges ahead, for example, wafer-scale integration. Commercial image sensors can integrate millions of pixels to deliver high-definition images, but this has not been implemented in our prototype yet,” he said. “This large-scale van der Waals semiconductor device integration is currently a critical challenge to be surmounted by the entire research society. Along with our nationwide collaborators that is where our team is devoting our efforts.”

The technology is patent pending with Georgia State’s Office of Technology Transfer & Commercialization (OTTC).