Smart contact lenses seem like a thing of the future, but the truth is that they are a reality. The advancement of technology has encouraged the appearance of different models, such as some that prevent blindness caused by diabetesa disease very present in Spain, or other augmented reality with the smallest screen in the world. Now thanks to a new technique for printing electronic circuits on curved surfacesthese devices can also measure fluid pressure in the eye to detect if you have glaucoma.
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A group of scientists from North Carolina State University, in the United States, has developed a new technique that simplifies the process of printing circuits on curved surfaces, something that until now was a great challenge. An innovative method that has great potential in enabling the creation of new types of electronic devicessuch as smart contact lenses, of which the researchers themselves have already manufactured a prototype.
This new process addresses two problems with existing techniques for printing circuits on surfaces. The first is that the conductive inks that are used often have polymer binding agents added to help them initially adhere to the substrate material. But these in turn affect conductivity, so an extra step is required to remove them after printing the circuit. The second challenge is that these circuits can usually only be printed on flat surfaces, and this is where this project comes in.
Straight: curved circuits
“We have developed a technique that does not require binding agents and that allows us to print on a variety of curvilinear surfaces. It also helps us to print the circuits as grid structures with a uniform thickness,” explains Yuxuan Liu, one of the authors of the project, in an official statement. But what does this technology really consist of?
This ingenious technique begins with the creation of a template that incorporates a specific pattern of microchannels, which is then used to replicate that same pattern on a thin film of elastic polymer. The researchers then adhere this flexible membrane to the surface of a given object, channel side down, which can be either flat or curved.
The electronic circuit on other surfaces.
Omicron
Then the little grooves in the polymer are filled with a liquid solution containing silver nanowires and ethanol, but without binder; then let it dry at room temperature. Once fully dry, the membrane is removed, leaving a fully functional circuit of silver nanowires that conforms to the contours of the object’s surface.
To demonstrate this technique, researchers at the American university have created several proof-of-concept prototypes. Among them are smart contact lenses that could be used for measure fluid pressure in the eyewhich is what the ophthalmologist performs in a tonometry exam to check for glaucoma and to check how well treatment is working if you have the disease.
Glaucoma affects more than 3% of the population in Spain, according to a study by the Spanish Glaucoma Society. This is a group of eye diseases that are related to increased pressure and can cause vision loss and blindness by damaging the nerve at the back of the eye, also known as the optic nerve. Therefore, its early detection and diagnosis is very important, since its treatment and prognosis are improved in its initial phases.
more prototypes
The researchers also made two other prototypes with this technique of printing electronic circuits on curved surfaces. The first of these was a transparent, flexible electrode with a grid pattern that could be used in solar cells or in touch panels.
On the other hand, a latex glove was created that had integrated pressure sensors that could give robots or prosthetics a sense of touch. Some inventions that demonstrate how this technique could have promising applications in optoelectronic and personal health monitoring devices.
The researchers also point out that this printing method can be extended to other nanomaterials for large-scale printing of high-performance soft electronic components. “We think this could be scaled up quite easily, in terms of manufacturing. We are open to talking with industries that are interested in exploring the potential of this technique,” says Yong Zhu, another lead author.