Mark Zuckerberg has been clear and outspoken about his belief that some type of glasses will eventually replace smartphones as our go-to computing device. Facebook is already spending R&D resources on developing those stylish glasses. Today we see a new patent that offers some clues: The AR glasses design uses an optical technology similar to that used in Microsoft’s HoloLens and in an upcoming product from Google-backed Magic Leap. The technology senses the real-world view of the wearer and place digital objects within it.

The patent lists three Oculus (owned by Facebook) engineers as the inventors. Business Insider points out that one of the patent authors, Pasi Saarikko, led Microsoft’s HoloLens group until moving to Facebook in 2015. The design shown in the patent is far smaller and sleeker than the HoloLens headset. Analysts say, however, that the components needed for such a small form factor are not yet available in large numbers.

But it’s crucial for Facebook to be doing this research now rather than later. Facebook has long wanted to control the hardware on which people experience Facebook services. That’s the reason for the ill-fated “Facebook phone” and the main reason it bought Oculus and its virtual reality headset product. When personal computing does finally collide with augmented reality headwear, Facebook wants to be there with a product.