Rumors that Apple is working on augmented reality glasses have been growing for some time, and a patent application published today shows how the same approach might be adapted to both a smartphone screen and smart glasses. It also describes how the two devices might be used in tandem.

We first heard back in March that Apple was aiming to debut AR features on the iPhone before later launching smart glasses, with a leaked document later suggesting that the company has gotten as far as testing prototypes.

These reports have been echoed since, with one analyst suggesting this might be behind Apple’s $200M investment in glass supplier Corning, which also makes the Gorilla Glass used in iPhones.

The patent published today was the work of AR software developer Metaio, which Apple acquired back in May. A number of its patents have since been assigned to Apple, including an earlier one covering AR use for interior design and animated movie posters.

Spotted by Patently Apple, today’s patent illustrates AR being used both on a smartphone only, and in a hybrid approach where augmented images appear on both smart glasses and phone. The idea is that the user can use the phone to interact with images seen in the glasses.

The patent was filed in April of this year and published today. As always, it’s worth noting that Apple patents all kinds of tech that never make it to market, but given the company’s enthusiasm for augmented reality, rumors about smart glasses do seem at least credible some way down the line.

Mockup: Stuff