Digital contact lenses that could eventually overlay Google Glass style data on top of the real world, while being as comfortable and discrete as traditional corrective lenses, have been developed by researchers at Samsung Display and elsewhere. The project – to develop a transparent, flexible display using graphene-metal nanowire hybrid structures to construct stretchable electrodes – published in Nano Letters uses a custom material to mount an LED onto a standard soft contact lens, while still retaining 94-percent transparency to light.
The lens won’t ready for mobile data consumption any time soon, however. Currently it can only show in effect a single pixel, which means it’s unsuitable for anything but the most basic of information display. However, the team behind it – let by Ulsan National Institute of Science and Technology engineer Jang-Ung Park – hopes to “make a wearable contact-lens display that can do all the things Google Glass can do” given time.
Although Park’s project isn’t the first to embed a display into a contact lens, it promises to be the most comfortable to-date. Previous systems have relied on hard lenses, reducing the comfort of the eyewear to the user; that’s because they’ve had to make sacrifices to accommodate indium tin oxide, a conductive material which is transparent but inflexible.
It also requires high temperatures in order to apply it, temperatures which would be enough to destroy a soft contact lens. Instead, Park and counterparts at the University of Illinois at Urbana-Champaign, Samsung Research, and elsewhere, found that they could layer silver nanowires with sheets of graphene, reducing the overall electrical resistance of each material alone.
Applying the new material to a soft lens is a simple case of spinning the lens and then dripping it with liquid solutions. The result is flexible and stretchable – capable of withstanding 27-percent in bending strain, and 100-percent in tensile strain – and can have an LED mounted onto it for display purposes. Initial testing suggests the lenses cause no damage when worn for extended periods, though so far it seems the researchers have limited that to five hours at most.
The possibilities for the lenses – not to mention the conductive material – go beyond discrete displays, however. One offshoot being explored is turning the contact lenses into wearable biomonitors, tracking the chemistry of the eye to pinpoint health issues, while another team is looking at how lenses could actively filter out light for vision correction.
When any of this advanced eyewear will actually make it to our bathroom cabinets remains to be seen, however, and similarly unclear is how expensive the lens technology might be. Replacing an eye-mounted display every day, or even every week, could quickly become exorbitant if the lenses themselves weren’t relatively low cost, though versions with limited diagnostic functionality might be more cost-effective.