The team of Dr. Seol Seung-Kwon and of Professor Lim-Doo Jeong have developed the core technology for smart contact lenses. These lenses are printed using a 3D printer and are worn like normal lenses. Although the research on the lens is currently being conducted on diagnosing and treating health, the smart contact lenses could be used for AR based navigation.
Dr. Seol Seung-Kwon’s Smart 3D Printing Research Team at KERI and Professor Lim-Doo Jeong’s team at Ulsan National Institute of Science and Technology (UNIST) developed the core technology for smart contact lenses. A smart contact lens is a product attached to the human eye like a normal lens and provides various information. Research on the lens is being conducted mainly on diagnosing and treating health.
Smart contact lenses for AR
Even though the research on smart lenses is currently focused on health care, the researchers think the main application will be AR navigation. By wearing the lens, navigation should unfold in front of a person’s eye through AR. This is also interesting for games such as Pokemon Go in which gamers use their smartphone to see game elements with AR. Therefore, the research team expects that this new smart lens will attract a lot of attention.
Dr. Seol Seung-Kwon of KERI said, “Our achievement is a development of 3D printing technology that can print functional micro-patterns on non-planner substrate that can commercialize advanced smart contact lenses to implement AR. It will greatly contribute to the miniaturization and versatility of AR devices.”
Many obstacles for smart contacts
Even though the developments of the smart lenses are promising, many obstacles to commercialization exist due to severe technical challenges. But Seung-Kwon’s and Jeong’s teams have now iterated on the existing lenses by developing a technology that can realize AR by printing micro-patterns on a lens display using a 3D printer without applying voltage. The key is the Meniscus of used ink, which is a phenomenon in which a curved surface is formed on the outer wall without water droplets bursting due to capillary action when water droplets are gently pressed or pulled with a certain pressure.
In implementing AR with smart contact lenses, electrochromic displays that can be driven with low power are suitable. A “Pure Prussian Blue” color, with high price competitiveness and quick contrast and transition between colors, is attracting attention as the lens’ material. Prussian blue is crystallized through solvent evaporation in the Meniscus formed between the micronozzle and the substrate.
The scientific process of Meniscus and Prussian Blue
The researchers shared the scientific process that happens when the ink-filled micronozzle and substrate come in contact in a statement: “The Meniscus of the acidic-ferric-ferricyanide ink is formed on the substrate when the ink-filled micronozzle and substrate come in contact. Heterogeneous crystallization of FeFe(CN)6 occurs on the substrate within the meniscus via spontaneous reactions of the precursor ions (Fe3+ and Fe(CN)3−) at room temperature. Simultaneously, the solvent evaporation is occurred at the meniscus surface.”
“When water evaporates from the meniscus, the water molecules and precursor ions move toward the meniscus surface by convective flow, generating a preferential accumulation of the precursor ions in the outer part of the meniscus. This phenomenon induces the edge-enhanced crystallization of FeFe(CN)6; this is crucial for controlling the factors that influence the crystallization of FeFe(CN)6 in the printing step to obtain uniformly printed PB patterns on a substrate. As with conventional electroplating, the substrate used to have to be a conductor when voltage was applied, but a great advantage of using the meniscus phenomenon is that there is no restriction on the substrate that can be used because crystallization occurs by natural evaporation of the solvent.”
“Through the precise movement of the nozzle, the crystallization of Prussian blue is continuously performed, thereby forming micro-patterns. Patterns can be formed not only on flat surfaces but also on curved surfaces. The research team’s micro-pattern technology is very fine (7.2 micrometers) that can be applied to smart contact lens displays for AR, and the color is continuous and uniform.”
Learn more about these new smart contact lenses here
