Researchers have developed a new way to build augmented reality smart glasses that projects images directly into the eye rather than using lenses as a display. It's hoped the approach could shrink down smart glasses and AR headsets, potentially making them indistinguishable from day to day eyewear.

For now, this is theoretical and somewhat limited in scope. A prototype based on these methods would be capable of rendering texts and icons only. Projecting video into the eye wouldn't be possible at this stage.

"Rather than starting with a display technology and trying to make it as small as possible, we started with the idea that smart glasses should look and feel like normal glasses," research team leader Christopher Martinez of technology research institute Leti explains in a press release. "Developing our concept required a great deal of imagination because we eliminated the bulky optical components typically required and instead use the eye itself to form the image.

"We don't bring an image to the surface of the glass, but instead bring information that is emitted in the form of photons to make the image in the eye."

The design rapidly projects individual pixels into the eye, which the brain translates into an image. A combination of holographic optics and a semiconductor grid adjusts the phase and coherence of the photons to make sure the image is sharp.

For now, these are early designs and a working prototype is yet to be built. The researchers think the first model will have a 300 x 300-pixel monochrome display, though it should be possible to mount two of these one on top of the other. However, the technology isn't limited to square displays.

"Using a holographic element to form a retinal display is quite different from the traditional grid of pixels used for traditional displays," Martinez explains. "For example, information could be projected to the left and right portions of the field of view with no information in between, without increasing the complexity of the display."

The researchers say the technology could help people who experience compromised vision, with the projection compensating for any visual impairments to display text.

The research, See-through holographic retinal projection display concept, has been published in Optica and is available in full online. The researchers aim to build a working prototype and to ensure the safety of the technology.