Microsoft on Friday unceremoniously revealed new prototype augmented-reality (AR) glasses that look like a normal pair of thick-framed glasses. The emergence of the technology indicates Microsoft has been thinking ways to go beyond the bulky and costly HoloLens headset it unveiled two years ago.

"There's still a lot of work to be done," Microsoft researchers Andrew Maimone, Andreas Georgiou, and Joel Kollin wrote in a paper describing the glasses containing holographic display prototypes, which employ a technique called digital holography. The researchers will talk about their work at the Siggraph conference in Los Angeles in August.

The paper comes a few weeks after Facebook talked about building AR glasses. Snap, which sells camera sunglasses for its Snapchat messaging app, has introduced AR software features, although it has not yet indicated it's working on proper AR glasses. Apple is also thought to be developing AR technology.

AR generally involves superimposing virtual images on top of what you actually see. Virtual reality (VR), by comparison, entails completely covering your eyesight and showing you artificial imagery. The researchers did explore using their display prototypes for VR, although they noted that their more ambitious work lies in AR.

As a research endeavor, this new Microsoft hardware might not ever be mass-produced, although it does indicate some people inside the company are interested in exploring different shapes and sizes for its holographic technology.

"We show various capabilities of near-eye holographic displays (wide field of view, compact form factors, multi-focus, etc.) but we have not yet achieved all these capabilities in a single device," the researchers wrote. What they do have, they wrote, is a monoscopic tethered system. There is no way to track the movement of a person's head of eyes. Still, it's a start.